Avalanche Problems:

      1. Wind slabs

Fresh snow and strong winds has left and will continue to form touchy hard and soft wind slabs down-wind of ridgecrests and terrain features on all aspects in exposed treeline and alpine areas.

Travel Advice:

• Use caution as you transition into wind-exposed terrain and avoid freshly wind-loaded features.
• Use ridges and ribs to deke around large pillows of wind-transported snow at the top of slopes.
• When hill-climbing, turn back low in the slope before you hit any wind slabs near the top.
• Avoid exposure to terrain traps that can increase the consequences of getting caught in an avalanche.
• Give cornices a wide berth when travelling on or below ridges.

Avalanche Activity:

Recent observations from the Tumbler Ridge area include a couple of 25-35cm thick Size 1.5-2.0 natural wind slab avalanches on north through east facing alpine slopes. Closer to Prince George a natural Size 3 full-depth glide avalanche hit the Upper Torpy Road a few days ago.

Snowpack Summary:

Total snowpack depths are highly variable with exposed windward areas scoured to the ground and deep deposits on the downwind side of ridgecrests and terrain features. Surface crusts extend to ridgetops on south aspects, while on north aspects hard and soft wind slabs are bonding poorly to a hard crust.

At the base of the snowpack, a weak layer (most likely facets or depth hoar) has been acting as an avalanche failure plane during warm weather. It is common for basal weaknesses like this to start rearing their heads in the spring, when warmth and moisture penetrates the snowpack.

Cornices are very extensive and fragile in the Kakwa, but not so impressive in other parts of the region.

Weather Forecast:

An unstable air mass is expected to result in light snowfall throughout the forecast period with 5-10cm each day for Friday and Saturday and a little less on Sunday. Freezing levels could reach as high as 1000m during the day, and moderate southerly winds on Friday should shift to strong northeasterlies on Saturday and Sunday.

Prepared by Cam Campbell

Next Update Thursday, April 18, 2013.

Avalanche Problems:

      1. Cornices

Very large and fragile cornices can be found, especially in the Kakwa area. These can drop bus-sized chunks, which are a hazard in themselves, and can also trigger slabs on slopes below.

      2. Persistent Slabs

At high elevations, a buried layer of surface hoar may still be of concern. Most likely trigger points are steep, convex or convoluted terrain, and thin snowpack areas.

A weak layer at the base of the snowpack is also now reactive, especially on steep slopes that are being heated by warm temperatures, sun or rain.

      3. Loose wet

As skies clear next week, loose wet avalanches may occur on steep, sun-warmed terrain.

Travel Advice:

• Give cornices a wide berth when traveling on or underneath ridges.
• Be aware of deep persistent weaknesses which may be lingering. These can lead to very large avalanches. They are most likely to be triggered by surface avalanches stepping down, cornice falls, or by the weight of a person or sled on a thin-spot trigger point (e.g. a thin rocky area on a steep slope or moraine).
• Avoid travelling on or underneath slopes which are sporting glide cracks. Glide slabs can release unpredictably.
• Be alert to how snow conditions are changing with the influence of warming or sunshine, and choose appropriate terrain.

Avalanche Activity:

The recent hot weather caused a natural cycle of loose wet avalanches up to size 2, especially on steep, sun-baked slopes. In some areas, deep slabs were also releasing at ground. These were most prevalent on steep, smooth rock faces facing into the sun. Photo here.

Cornice fall was also triggering slabs in some areas, or just dropping bus-sized bombs on other slopes. As temperatures cool, avalanche activity is likely to drop off until the next significant change in the weather.

Snowpack Summary:

A very hot, dry week of weather led to a melt-freeze regime in most areas below about 2400 m. The snowpack surface was melting with the sun’s heat by day and refreezing at night. In the far south of the region, the upper 150 cm of the snowpack was reported to have reached 0 degrees, even at alpine elevations. Further north (around Pine Pass), the mild temperatures consolidated the snowpack and helped heal some weaknesses in the upper snowpack. A buried surface hoar layer in the upper snowpack could still be found, but has now become unlikely to be triggered. The highest elevation terrain in the region was reported to still be holding dry snow on shady, north-facing terrain. We have limited observations from these elevations, and it’s possible that persistent weaknesses are still lingering there.

At the base of the snowpack, a weak layer (most likely facets or depth hoar) has been acting as an avalanche failure plane during warm weather. It is common for basal weaknesses like this to start rearing their heads in the spring, when warmth and moisture penetrates the snowpack.

Cornices are very extensive and fragile in the Kakwa, but not so impressive in other parts of the region.

Weather Forecast:

Friday: An arctic front is forecast to bring light snow, light to moderate easterly winds and freezing levels near valley bottom.

Saturday: Light snow continues, with light winds. Freezing levels remain at valley bottom.

Sunday:  A brief gap between weather systems is expected to give drier conditions. Cloudy with sunny breaks. Trace to light precipitation.

Prepared by Penny Goddard

Next Update Thursday, April 11, 2013.

Avalanche Problems:

      1. Cornices

This time of year, very large cornices are usually overhanging north through east facing alpine slopes and with significant daytime warming and sun-exposure they will likely become unstable.

      2. Loose Wet

Steep, south facing slopes will shed easily with intense solar radiation.

      3. Persistent Slabs

At higher elevations, a buried layer of surface hoar may still be triggered on steep slopes, particularly those with convex terrain features. If an avalanche is triggered on this layer, it will likely be large and destructive.

Travel Advice:

• Avoid traveling on or under steep south-facing slopes during the day when the sun is out or temperatures are warm.
• Slopes with corniced entrances, or exposed to cornice falls should be avoided with these conditions.
• Be aware that not only are cornice falls a danger in themselves, but they may also trigger old wind slab or large deep slab avalanches on the slopes below.
• Deep persistent weaknesses can lead to very large avalanches that are most likely to be triggered by surface avalanches stepping down, cornice falls, or by the weight of a person or sled on a thin-spot trigger point (e.g. a thin rocky area on a steep slope or moraine).

Avalanche Activity:

Recent reports are limited to relatively harmless wet-loose avalanche activity on sun-exposed slopes, which is expected to continue with warm and sunny weather throughout the forecast period. Natural cornice falls are also a concern during daytime warming and cornices may also be easily triggered if you get too close.

Snowpack Summary:

There has been no new snow in the past week and recent winds haven’t been strong enough for significant new wind slab formation. Surface faceting and surface hoar growth is probably prevalent on shady slopes and at upper elevations, while the surface snow on sun-exposed slopes and at lower elevations has been subject to daily melt-freeze cycles. A report from the Pine Pass area on Sunday included easy sudden compression tests results down 10cm, moderate sudden results down 30cm, and hard resistant results down 50 cm, on a northeast facing treeline slope. But the recent warm temperatures have likely been promoting settlement and strengthening of these weaknesses. Deeper in the snowpack, a persistent weak layer of buried surface hoar likely still lingers. This weakness still has the potential to release large avalanches given a heavy trigger (like a cornice collapse), or a light trigger in the wrong spot (most likely over steep, convex, alpine features).

Weather Forecast:

Friday: 10-15cm of new snow with freezing levels in valley bottoms and temperatures in the -5 -10 Celsius range. Moderate winds are expected to be from the southwest in the southern part of the region, and from the northeast in the northern part of the region.

Saturday: Another 5-10cm of new snow with freezing levels remaining in valley bottoms and moderate westerly winds.

Sunday:  A brief clear and dry period is expected sometime Saturday afternnon or Sunday morning with and other 5cm or so sometime on Sunday. Temperatures dropping to -15 to -20 Celsius and light to moderate northeasterly winds.

Prepared by Cam Campbell

Next Update Thursday, April 4, 2013.

Avalanche Problems:

1. Storm Slabs

Recent storm snow is likely still reactive, especially where it has been blown into wind slabs in exposed alpine areas, or where it is exposed to solar radiation.

2. Persistent Slabs

At higher elevations, a buried layer of surface hoar may still be triggered on steep slopes, particularly those with convex terrain features. If an avalanche is triggered on this layer, it will likely be large and destructive.

3. Cornices

With significant daytime warming, cornices will become unstable. They are a danger in themselves, but may also trigger slabs on the slopes below

4. Loose Wet

Steep, south facing slopes will shed easily with intense solar radiation.

Travel Advice:

• Avoid steep, aggressive, alpine terrain.
• Avoid common trigger points such as convex rolls.
• Watch for signs of instability like recent avalanches, whumpfs, or shooting cracks. If observed, back off to lower angled terrain.
• If you are increasing your exposure to avalanche terrain, do it gradually as you gather information.
• Avoid traveling on or under steep south-facing slopes during the day when the sun is out or temperatures are warm.

Avalanche Activity:

We received reports of natural avalanche activity from Pine Pass last Friday, as well as a human-triggered wet slab avalanche near McBride at 1800 m running on the March 10^th surface hoar layer. There was a size 2 human-triggered avalanche in Pine Pass on Saturday in a wind slab deposit, with a crown depth that varied from 1 to 3 metres. There was further wind slab activity reported on Sunday. On Tuesday, there were several cornice releases reported, one of which released a size 3 slab avalanche on the steep convoluted slope below.

Snowpack Summary:

Most areas received around 30-40 cm new snow in the past week. During the early part of the storm, strong southwesterly winds set up touchy wind slabs, particularly on north to east aspects. More recently, winds have been light and have shifted round to the northwest. At elevations below approximately 1800 m, the new snow rests on a crust that formed as previous moist storm snow froze. Deeper in the snowpack, a weak layer comprising surface hoar crystals still exists. Where there is not a substantial crust in the snowpack, this layer still has the potential to release large avalanches given a heavy trigger (like a cornice collapse), or a light trigger in the wrong spot (most likely over steep, convex, alpine features).

Weather Forecast:

Friday: 10-15cm of new snow with freezing levels in valley bottoms and temperatures in the -5 -10 Celsius range. Moderate winds are expected to be from the southwest in the southern part of the region, and from the northeast in the northern part of the region.

Saturday: Another 5-10cm of new snow with freezing levels remaining in valley bottoms and moderate westerly winds.

Sunday:  A brief clear and dry period is expected sometime Saturday afternnon or Sunday morning with and other 5cm or so sometime on Sunday. Temperatures dropping to -15 to -20 Celsius and light to moderate northeasterly winds.

Prepared by JamesFloyer

Next Update Thursday, March 28, 2013.

Avalanche Problems

       1. Storm Slabs

Recent storm snow is bonding poorly to the previous snow surface and is particularly deep and weak in wind loaded areas. Natural avalanches large enough to bury a person remain possible especially during periods of heavy loading from snow and wind. People triggering avalanches is expected to remain likely throughout the weekend.

Travel Advice

• This is a good time to make conservative terrain choices.
• If you are increasing your exposure to avalanche terrain, do it gradually as you gather information.
• Avoid freshly wind loaded terrain features.
• Avoid common trigger points such as convex rolls.
• Watch for signs of instability like recent avalanches, whumpfs, or shooting cracks. If observed, back off to lower angled terrain.

Avalanche Activity

Reports from Wednesday include numerous natural slab avalanches up to Size 2. In alpine and treeline areas these were primarily limited to wind-loaded west through northwest aspects below ridge tops. While below treeline they were more widespread and started as moist loose-snow avalanches involving cohesionless surface snow before the slab released. On Sunday, we received a report of a skier triggered Size 1.5 20-30cm thick wind slab avalanche running on recently buried surface hoar on a northeast aspect in the McGregor Mountains. On Saturday afternoon a sledder triggered a sizable avalanche in a north facing wind-loaded chute near Tumbler Ridge

Snowpack Summary

Most areas received around 30-50cm of new snow since Tuesday. In some areas, above freezing temperatures between 1100-1600m resulted in moist storm snow at that elevation band. Recent snowpack tests on a northwest facing treeline slope in the McGregor Mountains gave easy sudden planar results on large surface hoar buried under this recent storm snow. Recent strong to extreme southeasterly winds have loaded leeward sides of ridge crests and terrain features in alpine and treeline areas. 

Weather forecast

Friday: 10-15cm of new snow with freezing levels in valley bottoms and temperatures in the -5 -10 Celsius range. Moderate winds are expected to be from the southwest in the southern part of the region, and from the northeast in the northern part of the region.

Saturday: Another 5-10cm of new snow with freezing levels remaining in valley bottoms and moderate westerly winds.

Sunday:  A brief clear and dry period is expected sometime Saturday afternnon or Sunday morning with and other 5cm or so sometime on Sunday. Temperatures dropping to -15 to -20 Celsius and light to moderate northeasterly winds.

Prepared by Cam Campbell

Next Update Thursday, March 21, 2013.

Avalanche Problems

       1. Loose Wet Avalanches

Sunny and mild weather through the weekend may trigger loose wet avalanches on open south-facing terrain at all elevations.

      2. Cornices

Mild temperature and sunshine may be enough to cause large fragile cornices to pop off. Not only are cornice falls a hazard in themselves, but they may also trigger a large slab avalanche on the slope below.

      3. Persistent Slabs

A layer of buried surface hoar and/or a crust is touchy and problematic in neighbouring regions. It is now around 100 cm deep in the Pine Pass area and 60-80 cm deep in Tumbler Ridge and McBride areas. A series of sun crusts are also found on solar aspects and have been active in recent avalanche activity.

Travel Advice

• Avoid large sun exposed slopes and overhead cornices if the sun is out in full force, especially if the snow surface is becoming moist or wet.
• Give cornices a wide berth when travelling on or below ridges.
• Be wary of travelling in thin, rocky or sparsely-treed areas, where triggering a persistent slab is more likely.
• Space out and look over your shoulder regularly when you’re riding a snowmobile to keep an eye on your buddies.
• Watch for signs of instability like recent avalanches, whumpfs, or shooting cracks. If observed, back off to lower angled terrain.

Avalanche Activity

Most neighbors to the south (North Columbias) reported widespread large slab avalanches up to size 3.5 during or after the storm that pushed through last weekend. Operators within the region reported surprisingly little activity during this period, but did observed numerous natural avalanches a couple days later, possibly after winds increased and the sun poked out. Many of the observed avalanches involved the recent storm snow and were from lower elevations.

Snowpack Summary

The storm last weekend dropped heavier snow in the south end of the region (~40-60 cm…maybe more) with much less further north. It’s likely that cornices continued to grow during the storm and may have reached their tipping point. The new storm snow has settled and gained strength over the past few days under drier conditions and mild temperatures. Most areas have at least one buried crust in the top 1 m of snow. A recent snowpack test in Kakwa Park gave hard “drops” result on a crust down 75 cm. Other areas still report a buried surface hoar layer, down 60-80 cm. This layer seems to be quite spotty and there is no new information on it since the last storm.

Weather forecast

Synopsis: A ridge of high pressure should maintain mostly sunny skies and mild temperatures through the weekend.  The freezing level should fluctuate from valley bottom overnight to 1200-1500 m during the day, with the warmest day being Saturday. Winds are generally light from the northwest but may rise to moderate or strong from the west late Saturday.

Outlook: The weather pattern changes early next week and we should see more cloud, cooler temperatures, and light precipitation for most of next week.

Prepared by Peter Marshall

Next Update Thursday, March 14, 2013.

Avalanche Problems

       1. Storm Slabs

Forecast snow and wind are likely to create new storm and wind slabs over the next few days. This will add to recent storm and wind slabs, and the extra weight could be enough to trigger buried persistent weak layers, creating surprisingly large avalanches.

      2. Cornices

Strong to extreme winds are likely to push many large cornices past their tipping point. Not only are cornice falls a hazard in themselves but they’re also likely to trigger large slab avalanches on the slope below.

      3. Persistent Slabs

A layer of buried surface hoar and/or a crust is touchy and problematic in neighbouring regions. It is now around 100cm deep in the Pine Pass area and 50cm deep in Tumbler Ridge and McBride areas. Deeper persistent weak layers from early February and late January, as well as basal facets in shallow snowpack areas remain a lingering concern as well.

Travel Advice

• There’s a good chance of another natural avalanche cycle over the weekend. Travel in avalanche terrain during periods of heavy loading from snow and wind is not recommended without professional-level safety systems or guidance.
• Be wary of travelling in thin, rocky or sparsely-treed areas, where triggering a persistent slab is more likely.
• Avoid freshly wind loaded terrain features. Convex rolls are prime places for triggering wind-loaded slopes.
• Space out and look over your shoulder regularly when you’re riding a snowmobile to keep an eye on your buddies.
• Give cornices a wide berth on ridges and avoid travelling underneath them.
• Watch for signs of instability like recent avalanches, whumpfs, or shooting cracks. If observed, back off to lower angled terrain.

Avalanche Activity

A lot of sluffing was observed on steep southerly aspects in Pine Pass last weekend. Some recent natural cornice fall and wind slab activity up to Size 2 was also observed on a northeast facing slope in the Tumbler Ridge area.

Snowpack Summary

Pine Pass got close to a metre of new snow late last week and over the weekend, while areas around Tumbler Ridge and McBride got half that amount. The recent warm weather has promoted settlement and bonding of this storm snow, but relatively dry new snow continues to accumulate and will need at least a couple of days to stabilize after the storms end. Recent snowpack tests produced hard resistant planar results on the old snow surface from earlier in the month; which is down around a metre and primarily crust in the Pine Pass area, but only 50cm deep and found to be buried surface hoar at treeline and below near McBride and Tumbler Ridge. The Alpine has seen a lot of wind.  Many SW faces are scoured down to bare rock; subsequently cornice growth and wind slab formation has been rampant. A report from Pine Pass included 20+cm wind slabs that were cracking around skis on cross-loaded slopes at treeline and above.

Weather forecast

Friday: A front is expected to stall over the region bringing 20-25cm of new snow for the western ‘upslope’ areas (e.g. Pine Pass and the McGregors), while areas further east (e.g. Tumbler Ridge and McBride areas) are only expected to get half that amount. Associated winds are expected to be strong southwesterlies and freezing levels could be as high as 1500m.

Saturday: Another 15-20cm of new snow is expected for westerly upslope areas with continued strong southwesterly winds and freezing levels close to 1700m.

Sunday:  A second frontal system is expected to bring heavier snow, at least to the southern part of the region, with freezing levels dropping back to valley bottoms.

Prepared by Cam Campbell

Next Update Thursday, March 7, 2013.

Rapidly increasing avalanche danger is likely from Friday 22 February onwards. We’d like to caution everybody against complacency in familiar terrain. It’s been a pretty good snowpack this season so far, but a change is on the wind. Venture out cautiously.  

Avalanche Problems

       1. Storm Slabs

Forecast snow and wind are likely to create a new storm slab problem over the next few days. This will add to recent storm slabs, and the extra weight could be enough to trigger buried persistent weak layers, creating surprisingly large avalanches.

       2. Persistent Slabs

A layer of buried surface hoar and/or a crust is touchy and problematic in neighbouring regions. It is likely to be currently buried by up to 30 cm of snow, and will become more deeply buried over the next couple of days. Deeper persistent weak layers from early February and late January remain a lingering concern as well.

       3. Wind slabs

Strong to extreme winds are likely to leave wind slabs on lee slopes, and cornices at ridge tops. Where winds have been particularly strong, you may encounter wind slabs lower in the start zone than usual. Wind slabs may linger as a problem after the stormy weather has ended.

Travel Advice

• There’s a good chance of a widespread natural avalanche cycle on Friday/Saturday. This represents a shift in conditions from most of the season thus far. Adjust your expectations and behaviour accordingly.
• Avoid avalanche terrain during periods of rapid loading from snow, wind or rain.
• Be wary of travelling in thin, rocky or sparsely-treed areas, where triggering a persistent slab is more likely.
• Avoid freshly wind loaded terrain features. Convex rolls are prime places for triggering wind-loaded slopes.
• Space out and look over your shoulder regularly when you’re riding a snowmobile to keep an eye on your buddies.
• Give cornices a wide berth on ridges and avoid travelling underneath them.
• Watch for signs of instability like recent avalanches, whumpfs, or shooting cracks. If observed, back off to lower angled terrain.

Avalanche Activity

No avalanches were reported this week.

Snowpack Summary

About 25 cm of snow fell near Pine Pass early this week, followed by light amounts of snow and light to moderate SW winds. Mainly mild temperatures helped settle the storm slab. Snowpack observations form the North Rockies were limited, but in the neighbouring Cariboos, a touchy surface hoar/sun crust layer buried around Feb 12 is the primary concern. Deeper persistent weak layers from early February and late January continue to show planar failures when moderate to hard forces are applied in snowpack tests. These deeper layers have not been reactive to the weight of a rider, but they may be triggered by large loads like an avalanche in motion (step-down avalanche), or a cornice fall.

Weather forecast

Friday: A cold front is expected to bring 15-20 cm snow and moderate to strong SW winds. Alpine temperatures near -5.

Saturday: Light snow or flurries. Moderate NW winds. Alpine temperature around -9.

Sunday:  A second frontal system is expected to bring moderate snow and extreme SW winds. Alpine temperature around -8.

Prepared by Penny Goddard

Next Update Thursday, Feb. 28, 2013.

Avalanche Problems

       1. Wind Slabs

Deep and touchy wind slabs have formed on the downwind of ridge crests and in cross-loaded gullies, particularly on northeast through southeast aspects and potentially well below the ridge crests. Triggering is likely in steep exposed terrain.

       1. StormSlabs

Up to 50 cm of storm snow has fallen in some parts of the region in the past few days. This new snow may not bond well to the underlying snow surface (old snow, wind slab, or sun crust) and could be triggered by the weight of a person or machine.

       2. Persistent Slabs

A layer of buried surface hoar and/or facets and/or a crust is reported down 70-100 cm. This problem may be present on all aspects and is more likely to be triggered in steep, open, convoluted terrain.

Travel Advice

• Give the new snow a few days to settle and gain strength before pushing into more committing terrain.
• Avoid freshly wind loaded terrain features. The higher you highmark, the more you risk triggering a wind-loaded slope.
• Watch for signs of instability like recent avalanches, whumpfs, or shooting cracks. If observed, back off to lower angle terrain.
• Start on small representative slopes with little or no consequence to gauge how reactive the recent storm snow is.
• Give cornices a wide berth and avoid steep sun exposed slopes if the sun is shining and the snow surface is becoming moist or wet.

Avalanche Activity

Several natural slab avalanches up to size 2.5 were reported from areas near Tumbler Ridge on Feb. 13. Most of these events were observed in wind loaded terrain and likely involved the recent storm snow. Explosive control work in the same area also produced slab avalanches up to size 3. Other areas reported isolated natural avalanches up to size 2 and a few small skier triggered avalanches.

Snowpack Summary

Up to 50 cm of storm snow fell earlier this week, accompanied by strong southwest winds. This formed deep wind slabs in lee terrain. Several buried sun crusts are present in the top 120 cm of snow on steeper south facing slopes. The January surface hoar layer is likely down 60-100 cm on sheltered shady slopes. There are no new reports about the sensitivity of this layer after the recent storm. The base of the snowpack is reported to be quite weak in eastern parts of the region. Avoid shallow snowpack areas, especially where new wind slabs have formed.

Weather forecast

Friday: Mainly cloudy with light snow early, followed by clearing. Winds are gusty and strong from the west-southwest. The freezing level is around 1200-1400 m

Saturday: Mainly cloudy with a chance of flurries. Winds are moderate from the west-northwest and the freezing level is around 1000 m.

Sunday: Mainly sunny and cooler. Winds should ease to light from the southeast and the freezing level drops to valley bottom.

Outlook: A progressive northwesterly flow pattern should bring weak disturbances across the region followed by brief ridging and sunny breaks throughout the week. Significant snow accumulations are unlikely and temperature should remain cool.

Prepared by Peter Marshall

Next Update Thursday, Feb. 21, 2013.

Thank you to those who have generously contributed their time and energy to sending in observations.  If you see something interesting in the field, please let us know about it. You can send observations to: forecaster@avalanche.ca, call (250) 837-6405, or post it on the North Rockies Discussion Forum.

Click here for the latest North Columbia-Cariboos Avalanche Forecast. The North Columbia-Cariboos is the next-door neighbour and conditions may be similar.

Avalanche Problems

       1. Wind Slabs

Touchy wind slabs are likely on the downwind of ridge crests on a variety of aspects. Winds slabs are most likely on northeast facing slopes, but anticipate wind slabs to form on southern and eastern aspects in response to forecast northwesterly winds.

       2. Persistent Slabs

A layer of buried surface hoar and/or facets and/or a crust exists between 40 and 80 cm. This problem is present on all aspects but is more likely to be triggered in steep, open, convoluted terrain.

       3. Deep Persistent Slabs

Depth hoar at the base of the snowpack remains a concern in areas with less snow. This deep persistent weakness is often prone to remote triggering and step down avalanches, and typical trigger points include thin rocky areas. Use extra caution if the sun is shining and temps are warm.

Travel Advice

• The snowpack is likely much more touchy now than it has been for much of the season due to a buried weak layer(s) in the upper snowpack.
• Give cornices a wide berth and avoid steep sun exposed slopes if the sun is shining and the snow surface is becoming moist or wet.
• Avoid freshly wind loaded terrain features. The higher you highmark, the more you risk triggering a wind-loaded slope.
• Watch for signs of instability like recent avalanches, whumpfs, or shooting cracks. If observed, back off to lower angle terrain.
• Start on small representative slopes with little or no consequence to gauge how reactive the recently buried snow is.
• Plan escape routes (what if the slope slides) and avoid terrain traps.
• Watch out for shallow and variable, rocky or sparsely treed areas where deep persistent weaknesses are more likely to be triggered.

Avalanche Activity

A few natural slab avalanches up to size 2 were reported on southerly aspects from areas near Tumbler Ridge earlier in the week. These were likely in response to warming and solar radiation. Explosive control also produced slab avalanches up to size 2.5 on N-NE aspects in the same area.

Snowpack Summary

Strong winds were a factor in the most recent storms. Both hard and soft wind slabs are likely in exposed N-NE facing terrain. Up to 80 cm of settling storm snow sits on a variety of old surfaces comprising of old wind slabs in exposed areas, surface hoar on shady slopes and a sun crust on slopes facing the sun. Recent snowpack tests produce resistant shears on the January surface hoar or facet layers on northerly aspects, and sudden “pops” shears down 100 cm on a sun crust on southerly aspects. Eastern parts of the region are still reporting a generally weak and shallow snowpack.

Weather forecast

Friday: Increasing cloud throughout the day. There is a chance of light snow in the evening or overnight as a weak system pushes across the northern BC. The freezing level is near valley bottom and winds are moderate from the northwest.

Saturday: Mainly sunny. The freezing level is around 1000 m. Winds are moderate from the northwest.

Sunday: Mainly sunny and warmer. The freezing level jumps to 1500 m. Winds remain moderate from the west-northwest.

Outlook: A strong ridge of high pressure of the coast of BC should maintain dry conditions, plenty of sunshine, and mild temperatures well into next week.

Prepared by Peter Marshall

Next Update Thursday, Feb. 14, 2013.

Thank you to those who have generously contributed their time and energy to sending in observations.  If you see something interesting in the field, please let us know about it. You can send observations to: forecaster@avalanche.ca, call (250) 837-6405, or post it on the North Rockies Discussion Forum.

Click here for the latest North Columbia-Cariboos Avalanche Forecast. The North Columbia-Cariboos is the next-door neighbour and conditions may be similar.

Avalanche Problems

       1. Wind Slabs

Fresh and touchy wind slabs have developed on the downwind of ridge crests on a variety of aspects, due to shifting recent winds. The primary aspect for wind loading is northeast facing slopes, but anticipate wind slabs to also exist on southern and eastern aspects.

       2. Persistent Slabs

A layer of buried surface hoar and/or facets and/or a crust exists between 40 and 70 cm. The most likely trigger points are on steep convex rolls on northern aspects.

       3. Deep Persistent Slabs

Depth hoar at the base of the snowpack remains a concern in areas with less snow. This deep persistent weakness is often prone to remote triggering and step down avalanches, and typical trigger points include thin rocky areas.

Travel Advice

• The snowpack is likely much more touchy now than it has been for much of the season due to a buried weak layer in the upper snowpack.
• Avoid freshly loaded wind slabs. The higher you highmark, the more you risk triggering a wind-loaded slope.
• Evaluate slopes for signs of recent avalanche activity, and feel for whumpfs, both of which indicate a potentially unstable snowpack.
• Start on small representative slopes with little or no consequence to gauge how reactive the recently buried snow is.
• Plan escape routes (what if the slope slides) and avoid terrain traps.
• Watch out for shallow and variable, rocky or sparsely treed areas where deep persistent weaknesses are more likely to be triggered.

Avalanche Activity

A few natural slab avalanches up to size 2 were reported from the region on Tuesday 29^th. These ran on steep convex features in the recent storm snow.

Snowpack Summary

Approximately 40-70 cm new snow has been added to the snowpack during storms in the last week. This new snow sits on a variety of old surfaces comprising of old wind slabs in exposed areas, surface hoar on shady slopes and a sun crust on slopes facing the sun. A mixture of northerly and southwesterly winds have moved snow into wind slabs on a variety of slopes in exposed areas.

Recent observations from the Tumbler Ridge area suggest that the snowpack remains generally shallow and faceted. The recent new snow will have added some new snow to the upper snowpack. Particularly on southern aspects, this new snow likely sits on a crust. In this area, depth hoar at the base of the snowpack remains a primary concern. In particular, small wind slab avalanches triggered near ridgelines could easily step down to the weak basal layers on the slope below, dramatically increasing the size and consequence of resulting activity.

Weather forecast

Friday: Light snowfall with low accumulations (2-5 cm) is expected with the passage of a warm front over the region. Freezing level around 1100 m. Moderate to strong southwesterly winds.

Saturday: Flurries possible, but mostly dry. Overcast. Freezing level around 1000 m. Light northwesterly winds.

Sunday: Moderate snowfall starting late in the day. Freezing level around 1200 m. Strong southwesterly winds in the afternoon/evening.

Prepared by James Floyer

Next Update Thursday, Feb. 07, 2013.

Thank you to those who have generously contributed their time and energy to sending in observations.  If you see something interesting in the field, please let us know about it. You can send observations to: forecaster@avalanche.ca, call (250) 837-6405, or post it on the North Rockies Discussion Forum.

Click here for the latest North Columbia-Cariboos Avalanche Forecast. The North Columbia-Cariboos is the next door neighbour and conditions may be similar.

Avalanche Problems

       1. Wind Slabs

Expect to find thick old stubborn and fresh thin wind slabs downwind of ridge crests and behind terrain features on southeast through northeast aspects.

       2. Deep Persistent Slabs

Depth hoar at the base of the snowpack remains a concern on slopes with smooth ground cover, particularly in shallower areas. This deep persistent weakness is often prone to remote triggering and step down avalanches, and typical trigger points include thin rocky areas.

Travel Advice

• Use caution as you transition into wind-affected terrain and avoid freshly wind-loaded features.
• Watch out for shallow and variable, rocky or sparsely treed areas where deep persistent weaknesses are more likely to be triggered.

Avalanche Activity

No recent avalanche activity has been reported. Only human-triggered activity in isolated areas, such as thin rocky slopes or freshly wind-loaded areas, is expected.

Snowpack Summary

Recent reports from the Pine Pass area suggest that the warm temperatures last week helped to settle and strengthen the snowpack. A surface crust also formed, particularly on sun-exposed slopes, which extends into treeline elevations, surface hoar growth and surface faceting was likely prevalent on sheltered shady slopes. Since then, there has been a light dusting of new snow with light to moderate southwesterly winds. A buried surface hoar layer from the beginning of January may be lingering in the upper snowpack, particularly on sheltered and shady slopes treeline and below.

Recent observations from the Tumbler Ridge area suggest that the snowpack remains generally shallow and faceted. Warm temperatures last week also helped to settle and strengthen the snowpack and formed a surface crust. Depth hoar at the base of the snowpack remains the primary concern.

Weather forecast

Mostly cloudy conditions are expected throughout the forecast period with light snow possible particularly in the western ‘upslope’ parts of the region. Freezing levels are expected to remain in valley bottoms with treeline temperatures around -5 Celsius. Winds should remain consistently moderate from the west or southwest.

Prepared by Cam Campbell

Next Update Thursday, Jan. 31, 2013.

Thank you to those who have generously contributed their time and energy to sending in observations.  If you see something interesting in the field, please let us know about it. You can send observations to: forecaster@avalanche.ca, call (250) 837-6405, or post it on the North Rockies Discussion Forum.

Click here for the latest North Columbia-Cariboos Avalanche Forecast. The North Columbia-Cariboos is the next door neighbour and conditions may be similar.

Avalanche Problems

       1. Wind Slabs

Expect to find fresh and touchy wind slabs downwind of ridge crests and behind terrain features on south through east aspects.

       2. Deep Persistent Slabs

Depth hoar at the base of the snowpack remains a concern on slopes with smooth ground cover, particularly in shallower areas. This deep persistent weakness is often prone to remote triggering and step down avalanches, and typical trigger points include thin rocky areas.

Travel Advice

• Use caution as you transition into wind-affected terrain and avoid freshly wind-loaded features.
• Watch out for shallow and variable, rocky or sparsely treed areas where deep persistent weaknesses are more likely to be triggered.
• Whumpfing, shooting cracks and recent avalanches are all strong indicators of an unstable snowpack. If observed, back-off to lower angled terrain.
• Be aware of the potential for remote triggering, wide propagations, and hard slabs pulling into low angled terrain.

Avalanche Activity

Reports from Wednesday in the Pine Pass area include evidence of natural avalanche cycle from Tuesday's strong northwesterly winds with thin wind slabs up to Size 2 in alpine terrain on specific cross-loaded features. Below treeline sun-exposure and warm temperatures resulted in snowballing and relatively harmless wet loose sluffs from steep south facing cutbanks.

Snowpack Summary

Recent observations from the Pine Pass area suggest that the recent wind event scoured ridges and loaded southerly aspects. Warm temperatures and sun-exposure has moistened the top 5-10cm on southerly aspects at lower elevations. Snowpack tests on a south facing treeline slope only produced hard resistant shears down 30cm with no shears evident in the mid-pack. However, two different buried surface hoar layers were recently observed in the Pine Pass area and may still be a concern in sheltered shady treeline areas. The first gave easy but resistant results in compression tests down around 20- 25cm last week. The second and most concerning gave moderate sudden results in compression tests, and showed a high propensity for propagating fractures in an Extended Column Test, last week when it was down around down 65- 70cm.

Recent observations from the Tumbler Ridge area suggest that the snowpack remains generally shallow and faceted. Throughout the past week the temperatures have been warm with a combination of snow and rain and lots of wind. Compression tests continue to give moderate sudden results down 70cm on large facets and depth hoar near the ground.

Weather forecast

Mostly cloudy conditions are expected throughout the forecast period with light snow possible particularly in the eastern part of the region. Freezing levels are expected to drop on Friday and remain at or near valley bottoms until Sunday afternoon, when another warm-up is possible. Winds should ease off on Friday with moderate westerlies on Saturday and light westerlies on Sunday.

Prepared by Cam Campbell

Next Update Thursday, Jan. 24, 2013.

There is limited information coming out of the North Rockies at this time. Thank you to those who have generously contributed their time and energy to sending in observations.  If you see something interesting in the field, please let us know about it. You can send observations to: forecaster@avalanche.ca, call (250) 837-6405, or post it on the North Rockies Discussion Forum.

Click here for the latest North Columbia-Cariboos Avalanche Forecast. The North Columbia-Cariboos is the next door neighbour and conditions may be similar.

Avalanche Problems

       1. Wind Slabs

Expect to find fresh and touchy wind slabs downwind of ridge crests, behind terrain features, and in cross-loaded gullies, even below treeline. Be aware that hard “drum-like” wind slabs are often prone to surprisingly wide propagations and can pull into incredibly low-angled terrain.

       2. Persistent Slabs

Two separate surface hoar layers buried in the upper snowpack are highly reactive to human triggers, especially where they are wind loaded.

Depth hoar at the base of the snowpack remains a concern on slopes with smooth ground cover, particularly in shallower areas. This persistent weakness is often prone to remote triggering and step down avalanches, and typical trigger points include thin rocky areas.

Travel Advice

• Avoid freshly wind-loaded features, highmark low on a slope, and use ridges and ribs to get below deep wind slabs near the top of the slope.
• Continually look for signs of unstable snow as you increase your exposure to avalanche terrain.
• Whumpfing, shooting cracks and recent avalanches are all strong indicators of an unstable snowpack. If observed, back-off to lower angled terrain.
• Remember that in wind-exposed terrain, particularly in the northeastern part of the region, the only slopes with enough snow for riding have probably been wind-loaded.

Avalanche Activity

Reports from last weekend in the Pine Pass area include a few a few cornice releases and 50-70cm thick wind slab avalanches in the Size 2 range on northeast aspects. Expect fresh wind slabs to be very touchy, especially where they are sitting on buried surface hoar. The deeper persistent weaknesses are more likely to be triggered from thin rocky areas, or from wind slabs stepping down.

Snowpack Summary

Two different buried surface hoar layers have been observed in the Pine Pass area. The first, probably now down around 20- 25cm recently gave easy but resistant results in compression tests. The second and most concerning is probably now down around down 65- 70cm and recently gave moderate sudden results in compression tests, and showed a high propensity for propagating fractures in an Extended Column Test.
Recent observations from the Tumbler Ridge area suggest most wind-exposed areas are completely scoured to ground, while deep drifts have deposited on leeward slopes and features. There has been 5-10cm of new snow in the past couple of days since, but the snowpack remains generally shallow and faceted. Last week compression tests gave moderate sudden results down 20cm on small fragmented surface hoar, and hard resistant results on depth hoar near the ground.

Weather forecast

A mix of sun and clouds with isolated light flurries is expected throughout the weekend. Light to moderate northwesterly winds and treeline temperatures in the -10 to -15 Celsius range. Forecast models are currently calling for a temperature inversion with significant warming at higher elevations to start on Sunday night.

Prepared by Cam Campbell

Next Update Thursday, Jan. 17, 2013.

There is limited information coming out of the North Rockies at this time. Thank you to those who have generously contributed their time and energy to sending in observations.  If you see something interesting in the field, please let us know about it. You can send observations to: forecaster@avalanche.ca, call (250) 837-6405, or post it on the North Rockies Discussion Forum.

Click here for the latest North Columbia-Cariboos Avalanche Forecast. The North Columbia-Cariboos is the next door neighbour and conditions may be similar.

Avalanche Problems

1.      Storm Slabs

New snow may not bond well to current snow surfaces including surface hoar and surface facets. Storm slabs will be most reactive during and within about 24 hours of a storm.

2.      Wind Slabs

Winds are likely to create new wind slabs behind terrain breaks like ridges, ribs and gully walls. Cornices may also develop or grow larger. Older buried wind slabs may be found on slopes lee to the west.

Travel Advice

• Conditions have been pretty stable recently and the riding has been great! A change in weather patterns means a change in snowpack conditions. You might not get away with travelling in the same terrain that you did last week.
• Scale back your exposure to avalanche terrain during stormy periods. Take time to test how the new snow is bonding before committing to a slope.
• Whumpfing, shooting cracks and recent avalanches are all strong indicators of an unstable snowpack. If observed, back-off to lower angled terrain.

Avalanche Activity

No avalanches have been reported.

Snowpack Summary

Around McBride and Valemount, the snowpack is reported to be generally well-settled, with no significant results in snowpack tests. A video from the Valemount area demonstrates this. Bear in mind that snowpack conditions can quickly change with new snow and/or wind. At the snow surface, large surface hoar crystals have been observed in some areas. This may bond poorly with incoming snow.

Near Pine Pass, a layer of surface hoar was buried on 27 Dec with light amounts of snow. Surface facets make up the upper portion of the snowpack. The snowpack height is around 140 cm at treeline and 180 cm in the alpine.

In shallow snowpack areas, persistent weak layers of facets and/or a crust may still be a concern. Please take the time to dig down and test the snowpack structure in your local area. These types of weaknesses can be triggered from thin snowpack areas or with a heavy load and can cause surprisingly large avalanches. I don’t have enough information to know how widespread or problematic they are in areas less travelled.

Weather forecast

Friday-Sunday: A series of weak frontal systems are expected to affect the area, bringing mainly light (or locally moderate) precipitation. Winds are forecast to increase from the west on Friday, and remain variable south-westerly to north-westerly. Temperatures are hovering around -8 in the alpine.

 Prepared by Penny Goddard

There is limited information coming out of the North Rockies at this time. Thank you to those who have generously contributed their time and energy to sending in observations.  If you see something interesting in the field, please let us know about it. You can send observations to: forecaster@avalanche.ca, call (250) 837-6405, or post it on the North Rockies Discussion Forum.

Click here for the latest North Columbia-Cariboos Avalanche Forecast. The North Columbia-Cariboos is the next door neighbour and conditions may be similar.

Avalanche Problems

1. 1.      Wind Slabs

Reportedly stiff, stubborn wind slabs exist downwind of ridge crests, behind terrain features, and in cross-loaded gullies. Although stubborn to trigger, be aware that hard “drum-like” wind slabs may be prone to surprisingly wide propagations.

1. 2.      Persistent Slabs

Facets or depth hoar at the base of the snowpack may be of concern on slopes with smooth ground cover, particularly in shallow snowpack areas. This persistent weakness is often prone to remote triggering and step down avalanches. Typical trigger points include thin, unsupported, rocky areas.

Travel Advice

• Be increasingly cautious as you transition into wind-affected terrain
• Continually look for signs of unstable snow as you increase your exposure to avalanche terrain.
• Whumpfing, shooting cracks and recent avalanches are all strong indicators of an unstable snowpack. If observed, back-off to lower angled terrain.
• Remember that in heavily wind-scoured terrain, particularly in the northeastern part of the region, the only slopes with enough snow for riding have probably been wind-loaded.

Avalanche Activity

During the past week there was a natural avalanche cycle reported to size 2.5 in the Pine Pass area. As much of the activity was specific to southern aspects, I would suspect that it was result of windslab development from extreme north winds.

Snowpack Summary

In the Pine Pass area, light amounts of new snow that fell before Christmas added to the generous amounts of new snow that fell the week before. Significant settlement has since taken place; however, strong to extreme northerly winds have also redistributed much of the surface snow into reportedly stiff, stubborn windslabs on south aspects. In more recent days, surface hoar crystals have grown on the snow surface and extremely cold temperatures have contributed to surface faceting. This weak surface structure will be the thing to remember as forecast light amounts of snow cover it up.

The mid snowpack in this area is reported to be fairly well-settled and strong. The facets/depth hoar near the ground have been reactive in compression tests in the moderate to hard range, but favorable temperature gradients seem to be rounding it out.  

Observations from the Tumbler Ridge area suggest most wind-exposed areas are completely scoured to ground, while deep drifts have deposited on leeward slopes and features.

Weather forecast

Very light snowfall is forecast for Thursday night and Friday. Moderate to strong southwest winds are expected to accompany the system with freezing levels jumping to 500m during the brief system. The ridge is expected to rebound by the weekend bringing mainly clear skies, colder ridgetop temperatures (-10.0 to -15.0) and moderate northerly winds.

There is limited information coming out of the North Rockies at this time. Thank you to those who have generously contributed their time and energy to sending in observations.  If you see something interesting in the field, please let us know about it. You can send observations to: forecaster@avalanche.ca, call (250) 837-6405, or post it on the North Rockies Discussion Forum.

Click here for the latest North Columbia-Cariboos Avalanche Forecast. The North Columbia-Cariboos is the next door neighbour and conditions may be similar.

Avalanche Problems

       1. Wind Slabs

Expect to find fresh and touchy wind slabs downwind of ridge crests, behind terrain features, and in cross-loaded gullies, even below treeline. Be aware that hard “drum-like” wind slabs are often prone to surprisingly wide propagations and can pull into incredibly low-angled terrain.

       2. Persistent Slabs

Depth hoar at the base of the snowpack remains a concern on slopes with smooth ground cover, particularly in shallower areas. This persistent weakness is often prone to remote triggering and step down avalanches, and typical trigger points include thin rocky areas.

Travel Advice

• Avoid freshly wind-loaded features, highmark low on a slope, and use ridges and ribs to get below deep wind slabs near the top of the slope.
• Continually look for signs of unstable snow as you increase your exposure to avalanche terrain.
• Whumpfing, shooting cracks and recent avalanches are all strong indicators of an unstable snowpack. If observed, back-off to lower angled terrain.
• Remember that in wind-exposed terrain, particularly in the northeastern part of the region, the only slopes with enough snow for riding have probably been wind-loaded.

Avalanche Activity

Reports from the Pine Pass area last weekend include a small Size 1, 40cm thick wind slab release on a steep lee feature, which appeared to have released on a facet layer in the upper snowpack. There was also evidence of slab releases on the western aspect of the Murray Ridge and in the east facing slopes above Powder King. I expect fresh wind slabs to be very touchy. The deeper persistent weaknesses are more likely to be triggered from thin rocky areas, or from wind slabs stepping down.

Snowpack Summary

Late last week 60cm of relatively warm and heavy new snow fell in the Pine Pass area, which caused rapid settlement of the previous very low density snow, and created an upside-down upper snowpack. Since then another 40-45cm of lower density snow has fallen bringing the treeline snowpack depth close to 2m and seemingly bottomless. The depth hoar near the ground is still reactive in compression tests in the moderate to hard range, but favorable temperature gradients seem to be rounding it out.  Compression tests also produced moderate resistant shears down 20-40cm on some faceted old storm snow.

Recent observations from the Tumbler Ridge area suggest most wind-exposed areas are completely scoured to ground, while deep drifts have deposited on leeward slopes and features. There has been 5-10cm of new snow in the past couple of days since, but the snowpack remains generally shallow and faceted. Last week compression tests gave moderate sudden results down 20cm on small fragmented surface hoar, and hard resistant results on depth hoar near the ground.

Weather forecast

Friday: Cloudy with light snowfall possible, valley bottom temperatures around -15 to -20 Celsius and light to moderate northeasterly winds. Saturday: Mostly sunny, valley bottom temperatures around -15 to -20 Celsius and moderate southeasterly winds becoming strong easterlies. Sunday: Cloudy with a chance of snow, valley bottom temperatures around -20 Celsius and moderate southeasterly winds.

Prepared by Cam Campbell

Next Update Thursday, Dec. 27, 2012.

There is limited information coming out of the North Rockies at this time. Thank you to those who have generously contributed their time and energy to sending in observations.  If you see something interesting in the field, please let us know about it. You can send observations to: forecaster@avalanche.ca, call (250) 837-6405, or post it on the North Rockies Discussion Forum.

Click here for the latest North Columbia-Cariboos Avalanche Forecast. The North Columbia-Cariboos is the next door neighbour and conditions may be similar.

Avalanche Problems

      1. Wind Slabs

Expect to find fresh and touchy wind slabs downwind of ridge crests, behind terrain features, and in cross-loaded gullies, even below treeline. Be aware that hard “drum-like” wind slabs are often prone to surprisingly wide propagations and can pull into incredibly low-angled terrain.

      2. Persistent Slabs

A depth hoar at the base of the snowpack remains a concern on slopes with smooth ground cover, particularly in shallower areas. This persistent weakness is often prone to remote triggering and step down avalanches, and typical trigger points include thin rocky areas.

Travel Advice

• Avoid freshly wind-loaded features, highmark low on a slope, and use ridges and ribs to get below deep wind slabs near the top of the slope.
• Continually look for signs of unstable snow as you increase your exposure to avalanche terrain.
• Whumpfing, shooting cracks and recent avalanches are all strong indicators of an unstable snowpack. If observed, back-off to lower angled terrain.

Avalanche Activity

Recent reports include human-triggered wind slabs avalanches at treeline and above and in large openings below treeline. Continued wind-loading throughout the weekend will likely result in natural avalanche activity, particularly on north through east aspects at treeline and alpine elevations.

Snowpack Summary

Recent observations from the Tumbler Ridge area suggest that the snowpack in that area is generally shallow and bottomless with 110cm at 1600m. While wind-exposed areas are highly variable with scoured faceted slopes and pockets of deep wind drifts. Compression tests gave moderate sudden results down 20cm on small fragmented surface hoar, and hard resistant results on depth hoar near the ground.

Recent observations from the Pine Pass area suggest the 125-165cm deep treeline snowpack is “right-side-up” with low density powder on the surface and incrementally increasing stiffness toward the base of snowpack, at least until the sugary depth hoar just off the ground.  Compression tests produced moderate resistant shears down 20cm, and hard resistant shears in the basal depth hoar.

Meanwhile in the Torpy Range recent reports suggest that the snowpack is very similar to the Pine Pass area, with lots of wind slab development last weekend.

Weather forecast

Friday: Expect the snowfall to taper off in the morning with 15-20cm of new snow on the western slopes but much less on the east side of the divide. Winds during the storm are expected to be strong southwesterlies and ease slightly as the snow tapers off. Freezing levels are expected to remain in or near valley bottoms. Saturday: Light snowfall throughout the day with 5-10cm possible, strong to extreme southwesterly winds and freezing levels remaining in valley bottoms.

Prepared by Cam Campbell

Next Update Thursday, Dec. 20, 2012.

There is limited information coming out of the North Rockies at this time. Thank you to those who have generously contributed their time and energy to sending in observations.  If you see something interesting in the field, please let us know about it. You can send observations to: forecaster@avalanche.ca, call (250) 837-6405, or post it on the North Rockies Discussion Forum.

Click here for the latest North Columbia-Cariboos Avalanche Forecast. The North Columbia-Cariboos is the next door neighbour and conditions may be similar.

Avalanche Problems

     1. Wind Slabs

Lots of very low density snow available for wind-transport is keeping wind slabs fresh even under light winds. Expect to find weak wind slabs downwind of ridge crests, behind terrain features, and in cross-loaded gullies, even in valley bottoms.

     2. Persistent Slabs

A facet/crust combination at the base of the snowpack, or depth hoar in shallower areas, is a concern on slopes with smooth ground cover. This persistent weakness is often prone to remote triggering and step down avalanches, and typical trigger points include thin rocky areas.

     3. Dry Loose

Very low density surface snow is sluffing readily on steep sheltered slopes. Although generally small, they could take you for a ride.

Travel Advice

• Avoid freshly wind-loaded features, highmark low on a slope, and use ridges and ribs to get below deep wind slabs near the top of the slope.
• Certainly time to pay attention to conditions, and continually look for signs of unstable snow as you increase your exposure to avalanche terrain.
• Whumpfing, shooting cracks and recent avalanches are all strong indicators of an unstable snowpack. If observed, back-off to lower angled terrain.
•  Be aware of the potential for remote triggering and avoid travelling directly below steep open slopes.
• Pull over periodically or cut into a new line to let your sluff run by, and avoid exposure to terrain traps below.

Avalanche Activity

Several ski cuts on a steep 30 plus degree slope near Pine Pass only produced sluffing. Expect fresh wind slabs to be very touchy with the potential to step-down to deeper weaknesses.

Snowpack Summary

Snowpack depths are close to average for this time of year with 100-150cm at treeline in the western ranges (Torpy, Pine Pass, Renshaw), and up to 2 metres in alpine areas. There is less snow east of the divide (Chetwynd, Tumbler Ridge) but still close to a metre in some areas. In sheltered areas the snowpack is very low density and bottomless, while wind-exposed areas are highly variable with scoured faceted slopes and pockets of deep wind drifts.

Recent observations from around the region confirm a widespread rain crust around 20-30cm above ground with a thick layer of facets on either side that have been producing consistent moderate to hard but sudden collapse results in compression tests. Weaknesses also exist within and under the recent storm snow with easy sudden planer shears down 90cm in the Pine Pass area. Small surface hoar found down 15cm below treeline near Tumbler Ridge gave easy sudden collapse compression test results, and a couple of moderate resistant fractures were also observed in the mid-pack at this location.

Weather forecast

Friday and Saturday: Expect a gradual clearing trend with little in the way of new snow. Winds are expected to be light northwesterlies and alpine temperatures in the -10 to -15 Celsius range. Sunday: Increasing cloud and 5-15cm of snowfall as winds shift to strong southwesterlies. Alpine temperature remaining around -10Celsius but warm air aloft could cause another temperature inversion.

Prepared by Cam Campbell

Next Update Thursday, Dec. 13, 2012.

There is limited information coming out of the North Rockies at this time. Thank you to those who have generously contributed their time and energy to sending in observations.  If you see something interesting in the field, please let us know about it. You can send observations to: forecaster@avalanche.ca, call (250) 837-6405, or post it on the North Rockies Discussion Forum.

Click here for the latest North Columbia-Cariboos Avalanche Forecast. The North Columbia-Cariboos is the next door neighbour and conditions may be similar.

Avalanche Problems

     1. Wind Slabs

Winds from various directions have created a highly variable snowpack in many alpine areas with soured areas and deep drifts. Expect to find weak wind slabs below ridgecrests, behind terrain features, and in cross-loaded gullies on unusual aspects.

     2. Persistent Slabs

A facet/crust combination, or depth hoar in shallower areas, is a concern on slopes with smooth ground cover. This persistent weakness is often prone to remote triggering and step down avalanches, and typical trigger points include thin rocky areas.

Travel Advice

• Certainly time to pay attention to conditions, and continually look for signs of unstable snow as you increase your exposure to avalanche terrain.
• Whumpfing, shooting cracks and recent avalanches are all strong indicators of an unstable snowpack. If observed, back-off to lower angled terrain.
•  Be aware of the potential for remote triggering and avoid travelling directly below steep open slopes.
• Remember that in wind-exposed terrain, particularly in the northeastern part of the region, the only slopes with enough snow for riding have probably been wind-loaded.

Avalanche Activity

There have been no reports of recent avalanches, but observations are very limited this time of year. Expect fresh wind slabs to be very touchy with the potential to step-down to deeper weaknesses.

Snowpack Summary

Snowpack depths are close to average for this time of year with around 75-100cm at treeline in the western ranges (Torpy, Pine Pass, Renshaw), and 110-150cm in alpine areas. But expect to find much less snow on the eastern side (Chetwynd, Tumbler Ridge) with only about 50cm on the ground.  A decent amount of early season snow in October was rained on in early November, leaving a hard crust near the ground in most areas. Subsequent snowfall has buried this crust and cold temperatures have caused the surrounding snow layers to facet and become weak. Recent snowpack tests in the Torpy Range gave moderate resistant results on this crust where s was found 30-35cm above the ground.

Weather forecast

Expect overcast skies and light snow throughout the weekend with maybe a couple of centimeters of accumulation on Friday, and 5-10cm each day for Saturday and Sunday. Strong southeasterly winds on Friday are expected to shift to southwesterlies late Saturday and ease off late Sunday. Freezing levels are expected to remain in the valley bottoms for the forecast period with daytime high treeline temperatures hovering around -10 Celsius.

Prepared by Cam Campbell

Next Update Thursday, Dec. 6, 2012.

There is limited info coming out of the North Rockies: a huge thank you to those who have generously contributed their time and energy to sending in observations.  If you see something interesting in the field, please let us know about it. You can send observations to: forecaster@avalanche.ca or call (250) 837-2141 ext. 230.

Click here for the latest North Columbia-Cariboos Avalanche Forecast. The North Columbia-Cariboos is the next door neighbour and conditions may be similar.

Recent Weather Summary:

Light amounts of recent snow fell on Thursday 12th. Prior to that, the region saw warm temperatures and lots of sunshine. Overnight freeze has been minimal in the last few days. Winds have been generally light.

Avalanche Problems

1.       Loose wet

Loose wet avalanches are likely on sun-exposed slopes during the day.

2.      Wet Slab

There is the potential for wet slabs during more prolonged periods of warm temperatures. These are most likely on south aspects but could also affect other aspects if temperatures become particularly warm.

 3.     Cornices

Cornices are reported to very large at this time and continue to fall off naturally during periods of strong solar radiation and warm daytime high temperatures.

Travel Advice

• Watch for isolated pockets of wind slab on convex (unsupported) slopes behind exposed ridgelines.
• Avoid steep south-facing slopes during periods of warm temperatures or any time the sun is shining.
• Cornices are reported to be very large at this time, and may fail naturally due to daytime warming. Avoid slopes beneath cornices, or cross them in the morning if there has been a good freeze.
• Take advantage of cooler parts of the day if you’re considering bigger objectives, or plan to travel below large avalanche paths.
• Re-group well outside of avalanche terrain. Large avalanches and cornice falls may travel further than you expect.

Avalanche Activity

Loose wet avalanches have been reported from the past week on solar aspects. With prolonged warming, the potential for larger wet slabs increases as temperatures gradually rise. Cornice falls could also trigger deeper persistent weaknesses that have been sleeping for the past few weeks.

Snowpack Summary

Light amounts of recent new snow have fallen over a sun-baked, temperature affected snow surface. The upper snowpack has settled considerably during the past week, with high temperatures and lots of sunshine. I suspect there are many areas that are starting to see isothermal snowpack conditions, which means that much of the snow has reached 0°C. When this occurs, melt water can percolate down through the snowpack. If the melt water is channelled along crusts, the ground or previous weak layers of concern, these interfaces can become destabilized and large avalanches can result. Steep, south aspect slopes are the most susceptible to this.

Deeper weak layers, notably a surface hoar layer buried around 100 cm, still exist within the snowpack. While we have not had any reports of activity on this or other deeper layers, bear in mind that increased cornice activity is likely during prolonged periods of warming and this could provide the heavy load required to wake up one of these monsters.

Weather Forecast

On Friday, 5-10 cm new snow is expected, focussed mostly on eastern upslope areas. The freezing level will lower to around 1200 m. Winds are expected to be moderate northeasterly. On Saturday, lingering moisture in the air could bring further light precipitation but by Sunday the region should become dry. Winds through the weekend should be light and freezing levels should hover between 1200 and 1500 m.

Prepared by: James Floyer

There is limited info coming out of the North Rockies: a huge thank you to those who have generously contributed their time and energy to sending in observations.  If you see something interesting in the field, please let us know about it. You can send observations to: forecaster@avalanche.ca or call (250) 837-2141 ext. 230.

Click here for the latest North Columbia-Cariboos Avalanche Forecast. The North Columbia-Cariboos is the next door neighbour and conditions may be similar.

Recent Weather Summary:

There was a bit of new snow again this week. Convective flurries gave a few centimetres here or there, and a more pronounced system gave moderate snow (~20cm) on Tuesday. The last few days have been mostly cloudy with moderate winds. When the sun has poked out it’s had some kick, but for the most part temperatures have been relatively cool. You can probably still find dry snow on higher north aspects. South aspects and lower elevations have gone through a melt-freeze cycle most days.

Avalanche Problems

1.      Wind Slabs

New wind slabs may have formed over the week, especially where snowfall amounts were higher. Expect to find deep pillows below ridge crests, behind terrain features, and in gullies on a variety of aspects.

2.       Loose wet

Loose wet avalanches are likely on sun-exposed slopes during the day. There is also potential for larger wet slabs if temperatures rise a little higher this week. These slides could be very large and destructive.

 3.     Cornices

Cornices are reported to very large at this time and continue to fall off naturally during periods of strong solar radiation and warm daytime high temperatures.

Travel Advice

• Use ridges or ribs to avoid deeper pockets of wind-loaded snow. Be particularly cautious on unsupported features and convex shaped rolls.
• Cornices are reported to be very large at this time, and may fail naturally due to daytime warming. Avoid slopes beneath cornices, or cross them in the morning if there has been a good freeze.
• Avoid sun-exposed slopes in the afternoon if the surface snow is moist or wet.
• The presence of deeply buried surface hoar gives the possibility for deep, destructive avalanches to occur. Watch for triggering on unsupported terrain with variable snowpack depths.
• Re-group well outside of avalanche terrain. Large avalanches and cornice falls may travel further than you expect.

Avalanche Activity

No new avalanches reported in the last few days, but there are very few reports coming in at this time of year. Expect loose wet avalanches on solar aspects when the sun is out, and the potential for larger wet slabs as temperatures gradually rise. Cornice falls could also triggered deeper persistent weaknesses that have been sleeping for the past couple weeks.

Snowpack Summary

Some flurries over the past week have probably added up to 20-30cm of new snow. Mild daytime temperatures have promoted good settlement in the past week. Solar aspects and all aspects below 1000-1200m are going through a spring melt-freeze cycle. Snowpack depths are still in the 300-400 cm range. Many areas in the region have record snowpack depths. A surface hoar layer buried mid-February is now up to 110cm deep. This persistent weakness is most pronounced on sheltered slopes (glades), but is gaining strength in most areas. I would still be cautious about this layer as it is showing hard yet sudden results in some snowpack tests. Below this, the midpack is well bonded and strong. There is a lingering concern of deep weaknesses in areas with a shallower snowpack (i.e. eastern parts of the region).

Weather Forecast

A ridge of high pressure should maintain sunny conditions for at least the next few days, but it looks like the pattern will persist for even longer. Winds should be light for the most part. Freezing levels should bounce between 1000-1500m during the day and at valley bottom overnight. We should see a gradual warm up through the weekend and into next week.

Prepared by: Peter Marshall

Next Update: Thursday April 12, 2012

There is limited info coming out of the North Rockies: a huge thank you to those who have generously contributed their time and energy to sending in observations.  If you see something interesting in the field, please let us know about it. You can send observations to: forecaster@avalanche.ca or call (250) 837-2141 ext. 230.

Click here for the latest North Columbia-Cariboos Avalanche Forecast. The North Columbia-Cariboos is the next door neighbour and conditions may be similar.

Recent Weather Summary:

There was a bit of new snow early in the week, about 10-15 cm in the Tumbler Ridge area. The West Twin weather site near McBride received a couple of mm per day during the week, however warm temperatures caused the snowpack to decrease from about 120 cm to 90 cm in the last seven days. In Revolution Creek at 1676 metres elevation, the remote weather site is showing more snow on the ground for this time of year than previously on record (recorded since 1984). There has been a warming trend over the past 4 days. Daytime highs have been about +7.0 at 1700 metres and overnight lows have been about -4.0. The recent winds have been mostly light and variable from the south or the east. There has been some strong solar radiation during clear skies and days with periods of broken skies. 

Avalanche Problems

 1.     Cornices

Cornices are reported to very large at this time and continue to fall off naturally during periods of strong solar radiation and warm daytime high temperatures.

2.      Persistent Slabs

There is a layer of surface hoar that is buried down about 100-120 cm in some parts of the region. Avalanches releasing on this layer are becoming less frequent, and operators are gaining confidence that large triggers are required. If the warming trend continues, large cornice falls may continue to propagate large slab avalanches on this layer. Unsupported slopes at lower elevations may release on this layer due to daytime heating and/or a lack of re-freeze overnight.

3.      Wind Slabs

Old windslabs should have bonded on most aspects. Some old windslabs may continue to linger on shaded slopes in the high alpine.

4.       Loose wet

Melt-freeze crusts have developed on southerly aspects up to about 2400 metres and on all aspects up to about 1800 metres. The freezing level has only gone down to about 900 metres for the last few nights. Daytime heating may cause natural avalanche activity.

Travel Advice

• Cornices are reported to be very large at this time, and may fail naturally due to daytime warming. Avoid slopes beneath cornices, or cross them in the morning if there has been a good freeze.
• Avoid sun-exposed slopes in the afternoon if the surface snow is moist or wet.

• The presence of deeply buried surface hoar gives the possibility for deep, destructive avalanches to occur. Watch for triggering on unsupported terrain with variable snowpack depths.
• Re-group well outside of avalanche terrain. Large avalanches and cornice falls may travel further than you expect.

Avalanche Activity

No new avalanches reported in the last few days. Some natural cornice falls that released slabs up to size 2.5 were reported from the McGregors last weekend.

Snowpack Summary

Some flurries over the past week did not add to the snowpack depths. Weather stations show settlements of 10-30 cm during the week. Snowpack depths are still in the 300-400 cm range, which is above average for this region at this time of year. A surface hoar layer buried mid-February is now buried up to 110cm deep. This persistent weakness is most pronounced on sheltered slopes (glades), but is gaining strength in most areas. I would still be cautious about this layer as it is showing hard yet sudden results in some snowpack tests. Below this, the midpack is well bonded and strong. There is a lingering concern of deep weaknesses in areas with shallow snowpack (i.e. eastern parts of the region).

Weather Forecast

Unsettled weather is forecast to bring periods of convective flurries to the region over the next few days. The long range forecast is not showing any major systems. Expect light variable gusty winds over the weekend combined with periods of strong solar radiation. Freezing levels should rise to about 1200 metres during the day over the weekend, and drop to about 800 metres overnight.

Prepared by: Tom Riley

There is limited info coming out of the North Rockies: a huge thank you to those who have generously contributed their time and energy to sending in observations.  If you see something interesting in the field, please let us know about it. You can send observations to: forecaster@avalanche.ca or call (250) 837-2141 ext. 230.

Click here for the latest North Columbia-Cariboos Avalanche Forecast. The North Columbia-Cariboos is the next door neighbour and conditions may be similar.

Recent Weather Summary:

Between the 16th and 18th of March the region saw about 20-30cm of new snow with light to moderate winds. More recently there have been only light accumulations with the sun making brief appearances.

Avalanche Problems

1.     Cornices

Significant cornice development has occurred this season. Cornices are expected to be large and weak, especially with forecast warming.

2.      Persistent Slabs

The reactivity of surface hoar (buried just over a metre deep) seems variable between drainages, and with elevation and aspect. In general operators are gaining increased confidence in this layer. Having said that, if this weakness was triggered, it could produce unexpectedly large and destructive avalanches. The chances of this happening will also increase with forecast warming. Watch for triggering in unspported terrain with variable snowpack depths.

3.      Wind Slabs

Recently formed wind slabs may exist in the lee (downwind) of exposed terrain features such as ridges, peaks and rolls. I suspect that they have gained considerable strength, but may react in steep, unsupported alpine terrain

4.       Loose wet

Forecast solar radiation indicates that there will most likely be an increase in avalanche activity on sun-exposed slopes.

Travel Advice

• Watch for growing cornices that are likely becoming unstable with the warm temperatures.
• Avoid sun-exposed slopes

• The presence of deeply buried surface hoar gives the possibility for deep, destructive avalanches to occur. Watch for triggering on unsupported terrain with variable snowpack depths.

Avalanche Activity

Numerous cornice collpases were reported in the south of the region. The cornice fall was up to size 2 and occurred in response to recent warming. None of the cornice fall was reported to have triggered slab avalanches on the slopes below.

Continued heightened avalanche potential exists with forecast solar warming.

Snowpack Summary

This weeks generally moderate snowfall accumulations added to total snowpack depths of generally around 300 cm and up to 420 cm in higher snow areas. The recent lower density accumulations overide widespread stiff wind slabs that formed last week . A surface hoar layer buried mid-February is now buried up to 110cm deep. This persistent weakness is most pronounced on sheltered slopes (glades), but is gaining strength in most areas. I would still be cautious about this layer as it is showing hard yet sudden results in some snowpack tests. Below this, the midpack is well bonded and strong. There is a lingering concern of deep weaknesses in areas with shallow snowpack (i.e. eastern parts of the region): be locally aware of the total height of the snowpack.

Weather Forecast

Trace amounts of snow are expected on Friday, but a clearing trend is expected to develop on Saturday with generally light southwest winds and freezing levels rising each day. This trend is expected until at least Monday.

Prepared by: Joe Lammers

Elevated avalanche danger continues to exist in the North Rockies region at this time. Travel with caution in the backcountry.

There is limited info coming out of the North Rockies: a huge thank you to those who have generously contributed their time and energy to sending in observations.  If you see something interesting in the field, please let us know about it. You can send observations to: forecaster@avalanche.ca or call (250) 837-2141 ext. 230.

Click here for the latest North Columbia-Cariboos Avalanche Forecast. The North Columbia-Cariboos is the next door neighbour and conditions may be similar.

Current Report:   New snow accumulations have been variable throughout the region with light accumulations in the Pine Pass area and slightly heavier storm snow totals further south. Winds have been generally moderate from the southwest with more recent reports of gusts reaching 125km/h. Needless to say, the avalanche danger remains elevated at this time . A conservative and disciplined approach to mtn travel is currently required as natural avalanches are happening.

Avalanche Problems

1.      Wind Slabs

Recent strong to extreme winds from the SW have set up stiff and reactive wind slabs in the lee (downwind) of exposed terrain features such as ridges, peaks and rolls.

2.      Cornices

Recent strong wind means that cornice development will have occurred. Cornices are expected to be large and weak.

3.      Persistent Slabs

The reactivity of deeply buried surface hoar seems variable between drainages, and with elevation and aspect. In general operators are gaining increased confidence in this layer. Having said that, if this weakness was triggered, it could produce unexpectedly large and destructive avalanches.

Travel Advice

• Be cautious as you transition into wind affected terrain.
• Be aware of the possibility of wide propagations due to the presence of hard wind slabs.
• It's not the time to go out and set the record high-mark right now.
• Watch for growing cornices that are likely becoming unstable with the warm temperatures.
• Avoid sun-exposed slopes
• The presence of deeply buried surface hoar gives the possibility for deep, destructive avalanches to occur at this time.

Avalanche Activity

Observations were extremely limited this week due to inclement weather; however, a natural avalanche cycle occurred in response to recent wind loading. Avalanches were reported to size 2.5.

Continued heightened avalanche potential exists with forecast solar warming.

Snowpack Summary

This weeks generally moderate snowfall accumulations added to total snowpack depths of generally around 300 cm and up to 420 cm in higher snow areas. Widespread stiff wind slabs now exist on lee terrain at higher elevations. A surface hoar layer buried mid-February is now burried up to 1m deep. This persistent weakness is most pronounced on sheltered slopes (glades), but is gaining strength in some areas. Below this, the midpack is well bonded and strong. There is a lingering concern of deep weaknesses in areas with shallow snowpack (i.e. eastern parts of the region): be locally aware of the total height of the snowpack.

Weather Forecast

Between Friday and Sunday, light snowfall will  give way to increasingly clear skies as winds remain light and variable. Freezing levels are expected to remain at surface.

Prepared by: Joe Lammers

Next Update: Thursday March 15, 2012

Elevated avalanche danger exists in the North Rockies region at this time. Travel with caution in the backcountry.

There is limited info coming out of the North Rockies: a huge thank you to those who have generously contributed their time and energy to sending in observations.  If you see something interesting in the field, please let us know about it. You can send observations to: forecaster@avalanche.ca or call (250) 837-2141 ext. 230.

Click here for the latest North Columbia-Cariboos Avalanche Forecast. The North Columbia-Cariboos is the next door neighbour and conditions may be similar.

Current Report

Significant storms have resulted in two natural avalanche cycles in the last week. Avalanche danger is elevated at this time. Travel cautiously and pay attention to clues of instability. If you see recent signs of instability, such as avalanche activity, whumpfs or shooting cracks as you travel, it's time to head to the safety of shallower-angled terrain. Consider the possibility of large avalanches at this time that could step down to lower weak layers. As as result, crossing or playing in large avalanche paths is not a good idea at this time.

1.      Storm Slabs

A total of around 80 cm new snow has fallen in the last week. This has set up storm slabs that have been running naturally and in response to human triggers. The bond between the new snow and the old snow was initially poor, although with time, this will improve.

2.      Wind Slabs

Recent strong winds from the SW and NW have set up touchy wind slabs in the lee (downwind) of exposed terrain features such as ridges, peaks and rolls.

3.      Persistent Slabs

Buried surface hoar is quite widespread but variable with elevation and aspect. The potential to propagate fractures across large distances makes remote-triggering and surprisingly large avalanches a concern.

Travel Advice

• The presence of deeply buried surface hoar gives the possibility for deep, destructive avalanches to occur at this time.
• Good terrain choices are shallower angled terrain and small, non-committing slopes at this time.
• It's not the time to go out and set the record high-mark right now.
• Watch for growing cornices that are likely becoming unstable with the warm temperatures.
  

Avalanche Activity

Two avalanche cycles have been reported in the last week. One occurred on 2nd and 3rd Mar, with natural avalanches running on a variety of aspects and at all elevations up to size 3. The second occurred in response to further loading by new snow and wind, and occurred on 7th and into 8th Mar, with avalanches up to size 2.5.

Continued heightened avalanche potential exists with ongoing warm temperatures and the possibility of additional new snow and high winds.

Snowpack Summary

Around 80 cm new snow added enough snow to push some areas into record snowpack depths. Total snowpack depth is generally around 300 cm and up to 420 cm in higher snow areas. A prominent surface hoar layer buried mid-February is now burried up to 1m deep. This persistent weakness is most pronounced on sheltered slopes (glades), but on south aspects below approximately 1000m warm temperatures and solar radiation largely broke it down while it was still on the surface. Below this, the midpack is well bonded and strong. There is a lingering concern of deep weaknesses in areas with shallow snowpack (i.e. eastern parts of the region): be locally aware of the total height of the snowpack.

Weather Forecast

Warm temperatures are expected to be a feature into Friday, with freezing levels around 1600 m. A pulse of precipitation is expected for Friday, with amounts in the 5-10 mm range. Winds are expected to be strong southwesterly.

For the weekend, ongoing convective flurries are likely, although many areas will remain dry. Winds should diminish but remain in the moderate range from the southwest. By Monday, temperatures should drop back down to the 800-1000 m range.

Prepared by: James Floyer

Next Update: Thursday March 15, 2012

There is limited info coming out of the North Rockies: a huge thank you to those who have generously contributed their time and energy to sending in observations.  If you see something interesting in the field, please let us know about it. You can send observations to: forecaster@avalanche.ca or call (250) 837-2141 ext. 230.

Click here for the latest North Columbia-Cariboos Avalanche Forecast. The North Columbia-Cariboos is the next door neighbour and conditions may be similar.

Field Report

Recent field reports are from Pine Pass, Azouzetta Lake, Table River, and Sekunka Drainage. Current Avalanche Problems are:

1.      Persistent Slabs

Buried surface hoar is quite widespread but variable with elevation and aspect. The potential to propagate fractures across large distances makes remote-triggering and surprisingly large avalanches a concern.

2.      Wind Slabs

Recent northerly winds have scoured many north aspects and loaded southwest aspects. Stiff wind slabs, described as ‘spooky’ are generally lurking below ridgecrests, behind terrain breaks, and in gullies.

Travel Advice

• Certainly time to pay more attention to conditions, and continually look for signs of unstable snow as you increase your exposure to avalanche terrain.
• Whumpfing, shooting cracks and recent avalanches are all strong indicators of an unstable snowpack. If observed, back-off to lower angled terrain.
•  Be aware of the potential for remote triggering and avoid travelling directly below steep open slopes.
• Avoid lee and cross-loaded terrain near ridge crests.

Avalanche Activity

There were a few Size 2 naturals late last week on southwest aspects above Azouzetta Lake, which were most likely triggered at the beginning of the wind event. Only minor more recent natural activity was observed, mostly in the form of sluffing.

Snowpack Summary

Total snowpack depth is generally in the 250-300cm range at lower elevations and over 400cm in the alpine. Surface hoar buried mid-February is generally down 30-65cm and popping easily with snowpack tests. This persistent weakness is most pronounced on sheltered slopes (glades), but on south aspects below approximately 1000m warm temperatures and solar radiation largely broke it down while it was still on the surface. Below this, the midpack is well bonded and strong. There is a lingering concern of deep weaknesses in areas with shallow snowpack (i.e. eastern parts of the region): be locally aware of the total height of the snowpack.

Weather Forecast

A series of moderately intense weather systems is expected to affect the region Friday through Sunday, with 10-20cm possible each day and associated strong westerly winds. Freezing levels are expected to remain at or near valley bottoms for the forecast period.

Prepared by Cam Campbell

Next Update Thursday March 8, 2012

The CAC has issued a Special Public Avalanche Warning for much of the province on Feb 23, 2012. The North Rockies is included in this warning: click on the red banner at the top of your screen for more information.

There is limited info coming out of the North Rockies: a huge thank you to those who have generously contributed their time and energy to sending in observations.  If you see something interesting in the field, please let us know about it. You can send observations to: forecaster@avalanche.ca or call (250) 837-2141 ext. 230.

Click here for the latest North Columbia-Cariboos Avalanche Forecast. The North Columbia-Cariboos is the next door neighbour and conditions may be similar.

Field Report

As much as 80 cm of new snow has fallen in the past few days with consistent westerly winds. Critical values have been reached in many areas; natural and human triggered avalanches are likely. Current Avalanche Problems are:

1.      Persistent Slabs

Up to 80 cm of new snow has fallen on to a widespread surface hoar layer. The new snow has settled into a cohesive slab and is possible to trigger in surprisingly low angled terrain.  This problem is found on all aspects and through all elevation bands, is very touchy and able to produce large, destructive avalanches.

2.      Wind Slabs

Strong westerly winds have built deep wind slabs in lee features in the alpine and at treeline. These slabs are very touchy and able to produce large, destructive avalanches.

Travel Advice

• Travel in avalanche terrain is not advised without extensive personal knowledge and experience or professional level safety systems and guidance.
• Avoid lee and cross-loaded terrain near ridge crests.
• Avoid open slopes with any steepness over 30 degrees.
• Whumpfing, shooting cracks and recent avalanches are all strong indicators of an unstable snowpack.

Avalanche Activity

We have reports of natural avalanches up to size 2.0 releasing in wind loaded features at treeline. I expect larger natural avalanches in the alpine. Riders have also seen cracking around their skis and have observed whumphing in low angled terrain.

Snowpack Summary

As much as 80cm of new snow has fallen in the past week.  This overlies a widespread surface hoar layer and sun crust on south aspects at treeline and below. Below this, the midpack is well bonded and strong. There is a lingering concern of deep weaknesses in areas with shallow snowpack (i.e. eastern parts of the region): be locally aware of the total height of the snowpack.

Weather Forecast

Expect clouds to build Friday with flurries developing later in the day. Up to 10cm snow is possible with temperatures reaching -10 and moderate southeasterly winds. Unsettled conditions will likely persist through the weekend, with another 10cm of new snow possible. Clearing skies are expected later Sunday and into Monday with colder temperatures and more westerly winds.

Prepared by Matt Peter

Next Update Thursday March 1, 2012

North Rockies

Do you ride in the Pine Pass, Renshaw, Chetwynd, the Kakwa, or any of the other great powder stashes north of the Yellowhead and east of Hwy 97? If you do, you’ll know that there has never been an avalanche forecast for your area. Why is that? Because the forecasters at the Canadian Avalanche Centre don’t have the data they need to create an accurate picture of the area’s snowpack and weather conditions.

What you do get is a weekly avalanche report, which isn’t the same thing as a forecast but it’s the best we can do with the limited information we get. We’d like to make the move to a full-blown forecast but this is a complex task. If you’re interested in making this happen, there are ways you can help.

What kind of data do we need?

To generate a daily avalanche forecast, the CAC needs a steady stream of professional-level weather and snow observations. Some of this data could be gathered by electronic monitoring systems such as remote weather stations. But the type of snowpack information we require depends on trained professionals who can be in the field on a daily basis throughout the winter.

Where does the data for the CAC’s other forecast regions come from?

The vast majority of the professional-level data that comes into the CAC’s forecast office is donated by over 110 private and public agencies whose business includes avalanche risk management. These include heli- and cat-skiing operations, avalanche control teams for highways and railways, and avalanche specialists for federal and provincial parks. This professional network is called InfoEx, short for Information Exchange. It’s unique to Canada, and the envy of alpine nations around the world. InfoEx has formed the backbone of Canada’s public avalanche forecasts for 20 years—since 1991. Unfortunately there are no InfoEx operations in the North Rockies. If you know of any companies who operate in avalanche terrain in this region please let us know, and we’ll work to enlist their help in data gathering. 

What about government funding?

The CAC receives support from the federal and provincial governments, and we work closely together to address ongoing needs for improvements to public avalanche safety programs. Government funding has been instrumental in helping the CAC achieve many goals over the past few years, and will play a role in the North Rockies project as well. But government support is only one aspect to improving services to this region.

How can I help?

Amateur observations

If you ride in the North Rockies, tell us what you’re seeing. Flip us a quick email and send some photos. Your observations can help a lot by filling in the blanks, or alerting us to something unexpected. We especially want to know if you’ve triggered an avalanche, or seen evidence of fresh avalanches. These bits of information help us form that picture we need before we can issue relevant and reliable safety advice. Send your information to forecaster@avalanche.ca.

Fund raising

Data is expensive. For a North Rockies forecast region, we estimate that we’ll need two, two-person field teams and four remote weather stations. For start-up costs we’re looking at about $250,000, for buying and installing weather stations, and purchasing trucks/trailers, snowmobiles, safety and communication equipment, etc. The annual operating costs for two teams will be around $180,000. 

If you want to help establish a forecast for this area, fund raising is a great place to start. Donations of things like professional-quality weather stations, snowmobiles and other equipment helps a lot too. The important thing to remember is that the funding needs to be sustainable—we don’t want to provide a North Rockies forecast for just a couple of years and then have to abandon it because the funding ran out. If you can help out with our fundraising efforts, contact the CAC directly at 250-837-2141.

The bottom line is what works for other parts of the province, isn’t going to work for this region. We need a different approach to establish a daily avalanche forecast for the North Rockies. Let’s do it by working together.

It can be a bit challenging to get information from the region, thankfully a few people have generously contributed their time and energy to sending in observations.  If you see something interesting in the field, please let us know about it. You can send observations to: forecaster@avalanche.ca

Click here for the latest North Columbia-Cariboos Avalanche Forecast. The North Columbia-Cariboos is the next door neighbour and conditions may be similar.

From The Field

While the region has largely been under the influence of high pressure for the last week, a disturbance was able to sneak over the ridge Sunday night, continuing into Monday.  The storm produced aprox. 15 cm of snow, the bulk of which fell on Monday.  While this isn’t a great deal of snow, there’s a catch.  This snow fell on large well preserved Surface Hoar in most locations.  (The exception is a suncrust that formed under the recent high pressure on slopes that face both south & west.)  As a result, the region saw a small avalanche cycle Tuesday.  Isolated wind slabs were still a factor Wednesday.

Avalanche Summary

Northwesterly winds formed Monday’s new snow into soft slabs which were reportedly very touchy on Tuesday.  Softslab avalanches to size 1.5 were reported as were small point release avalanches.  I suspect that there may have been some larger activity in big alpine terrain too.

Snowpack Summary

Below the new snow/surface hoar interface the snowpack is pretty well consolidated.  I’d be surprised to hear about any avalanche activity deeper than this problematic layer.

Weather Forecast

On Friday the region will likely see alpine sun with some valley fog which should burn off by lunch.  Winds will be light out of the SW with temperatures warming to near 0 Friday afternoon.  Saturday is expected to bring overcast skies, temps again near zero in the afternoon and scattered flurries.  The west side of the region will likely pick up 2 – 5 cm of snow while the east side should only see a trace.  On Sunday the west side will see just a trace of new snow while the east side will see between 1 -10 cm of snow. 

Summary

If I were headed out this weekend, I’d be concerned about how the new snow is interacting with the now buried Surface Hoar.  I suspect that the new snow may form shallow soft slabs that could be sensitive to human triggering.  There may even be some bigger avalanches swimming around out there, especially in steep terrain at and above treeline.

Prepared by Grant Helgeson

Next Update Thursday February 23, 2012

There is very little information coming out of the region. However, there are a few people who have generously contributed to the content used in this report & we’re super grateful for their efforts. If you see something interesting in the field, please let us know about it. You can send observations to: forecaster@avalanche.ca

Click here for the latest North Columbia-Cariboos Avalanche Forecast. The North Columbia-Cariboos is the next door neighbour and conditions may be similar.

From The Field

High and dry conditions this week have promoted settling of all the snow the region received over the last few weeks.  Last weekend a few minor instabilities were noted in test profiles, but I suspect that a week of benign weather has allowed these to heal.    

Avalanche Summary

The sun is gaining strength as we enter mid-February.  Much of the province experienced a natural avalanche cycle last weekend as cold dry snow had its first encounter with solar radiation.  In the North Rockies the following activity was reported from last weekend & early this week:

Slab avalanche, Murray Ridge, elev: 1200 m, aspect: E aprox. 250m wide

Slab Avalanche near Powder King, elev:  1200 m, S aspect, 50cm deep x 400m wide x 150m in length

Several Slab Avalanches with approximate crown heights of 100 cm were reported from the Kakwa, occurring on E and NE aspects.

The North Rockies report covers  a very large area, and this is by no means an exhaustive list of avalanche activity.  Think of it as more of a glimpse into a cycle that was likely widespread.

Snowpack Summary

Lots of new snow the past two weeks means well above average snowpack depths. I suspect there’s 150 cm or more snow now covering the weak layers from mid-January cold snaps in deeper snowpack regions.  Operators in adjacent regions are reporting large cornices.  With continued mild temperatures forecast for the weekend, it will be important to factor cornice fall into your decision making.  It’s possible for car sized chunks of cornice to fall from ridge crests.  It’s best to give these monsters a wide berth, do your best to avoid traveling underneath them.

Weather Forecast

It looks like dry & mild weather for the foreseeable future as high pressure continues to dominate the weather pattern for much of BC and Alberta.  Trace amounts of snow are expected Saturday night, continuing into Sunday, but no significant precipitation is expected.  Daytime temps will remain mild climbing to just below freezing during the day at 1500m, dropping back down to -10 or so overnight.   Winds are expected to be light & variable.

Prepared by Grant Helgeson

Next Update Thursday February 16, 2012

There is very little information coming out of the region. However, there are a few people who have generously contributed to the content used in this report & we’re super grateful for their efforts. If you see something interesting in the field, please let us know about it. You can send observations to: forecaster@avalanche.ca

Click here for the latest North Columbia-Cariboos Avalanche Forecast. The North Columbia-Cariboos is the next door neighbour and conditions may be similar.

From The Field

Up to 150 cm of new snow is reported from a series of storms that passed through the region in the past week. Storm snow amounts from the previous week were around 120 cm so there`s an abundance of snow in the region. There are two types of weaknesses in the upper snowpack (the storm snow):  wind slabs and storm slabs. I expect both are touchy at higher elevations right now. Watch the warmth & the sun for the next few days, they could trigger natural avalanches. Watch the big cornices looming over alpine slopes – the warm temperatures & solar radiation will likely weaken them.

Avalanche Summary

We received reports of two size 2 avalanches in the Kakwa region from 29-Jan, one on a south aspect at 1600m and one on a north aspect at 2000m. We haven’t received any avalanche reports from elsewhere in the region. However, that doesn’t mean they haven’t occurred, or that they won’t occur this week. It’s important to make your own observations in the mountains where you recreate. If I was out riding this weekend I’d watch the weather for both incoming solar-radiation and temperature inversions. It may be cool down low in the valley but up above treeline it’s warm and the sun is baking the slopes. This high elevation warmth may prevail both day & night.

Large cornices are likely to start dropping with warmth and solar radiation. Big cornice drops could trigger large slab avalanche that propagate widely across an entire slope, and even step-down to deeper layers.

Snowpack Summary

Lots of new snow the past two weeks means well above average snowpack depths. I suspect there’s 150 cm or more snow now covering the weak layers from mid-January cold snaps in deeper snowpack regions. Both these layers present a scenario for large avalanches with the right trigger – I’m thinking cornice fall, or even a sled cliff-drop onto a slope.

Weather Forecast

A dry and mild pattern is setting up across the west and is likely to remain for the entire week. A high pressure system means clear skies with lots of sunshine and light southerly winds. I would keep an eye open for temperature inversions. For example, the region could see +5 degree temperatures above 2000m on Friday & Saturday. Valley bottoms are likely to see wide temperature swings daily - quickly rising to above freezing during the day and falling overnight. However, at high elevations warm temperatures may prevail day & night. No precipitation is forecast.

Prepared by ilya storm

Next Update Thursday February 09, 2012

There is very little information coming out of the region. However, there are a few people who have generously contributed to the content used in this report & we’re super grateful for their efforts. If you see something interesting in the field, please let us know about it. You can send observations to: forecaster@avalanche.ca

Click here for the latest North Columbia-Cariboos Avalanche Bulletin.

From The Field

Up to 120cms of new snow from several different storms has fallen over the North Rockies in the past week. The winds have again changed direction, and are now blowing from the SW-W. This means new wind slabs will be forming in the alpine and at treeline on N-E slopes. Last week’s wind blew from the NW-N. This creates a situation of variable buried wind slabs on southerly slopes, and new fresh wind slabs on the north-easterly slopes. The weekend to come is filled with strong westerly ridgetop wind, new snow, and rising freezing levels. The current avalanche problems will be wind slabs and storm slabs. I suspect these will be very touchy over the weekend. It may be a good time to wait out the weather, and let the new storm snow have a chance to settle and stabilize. If you are headed out into the backcountry I suggest staying out of avalanche terrain during times of heavy loading (snow, wind, rain). Make snowpack and weather observations as you travel, pick conservative lines and test very small slopes below treeline for instability. Don’t re-group in run-out zones and keep good spacing between riders if you’re crossing through or below an avalanche path. Keep your head up, and have a safe weekend!

Avalanche Summary

On January 21^st a natural slab avalanche was reported.  It occurred on a NE aspect near 1700m. The crown was 300m wide, the depth was 15cms deep, and the failure plain was facets. This occurred outside the Powder King Ski area boundary. The reporting party suspects Pine Pass area may have seen similar avalanches.

Snowpack Summary

During the Arctic Outbreak (last week’s cold, dry spell) surface hoar and surface facets formed. Then, the North Rockies received significant snowfall amounts up to 70cms. This new snow was dry with low density (blower!) weight to it. This snow fell on variable layers including wind slabs in the alpine, treeline, and in sheltered locations it fell on a fairly cohesive snowpack with weak surface layers (surface hoar, facets). Over the past couple of days 50-60cms of new snow has fallen. This new snow seems to be heavier, and rests on the lower density stuff below. This may create the perfect recipe for an avalanche cycle. Total snowpack depths at 1600m are 250-350cms.

A recent test profile dug near Powder King on January 22^nd showed several different sudden planar results in the easy to moderate ranges. The easy shears failed down 30cms in the snowpack on a wind slab and new snow interface. The moderate results were down 70cms on facets and mixed forms. With more snow, wind, and rising freezing levels this weekend the load will increase, and I suspect these layers may fail.

Weather Forecast

A frontal system will move into the region this weekend resulting in strong Westerly ridgetop winds, moderate precipitation and rising freezing levels. Friday snow amounts 10-20cms. Saturday snow amounts up to 30cms with freezing levels near 800m. Sunday snow amounts 5-12cms. Freezing levels 800m falling to valley bottom on Monday. Early next week, mainly dry & cloudy conditions, light-moderate W-SW winds, temperatures trending to seasonal values with freezing levels back at valley bottom.

Prepared by Shannon Werner

Next Report will be issued on February 2^nd, 2012

Overview

There is very little information coming out of the region.  However, there are a few people who have generously contributed to the content used in this report & we’re super grateful for their efforts.   If you see something interesting in the field, please let us know about it.  You can send observations to: forecaster@avalanche.ca

Current Situation

Winds were out of the SW until last weekend when there was a big shift.  What happened?  Well, Arctic air moved in from the north switching winds to the NE and dropping the temperature to the bone chilling end of the spectrum.  A Wx station at 1400 m has recorded overnight lows near – 30 all week.  As you move up in elevation temperatures continue to drop. 

These Arctic winds are reverse of the normal pattern, so we refer to their affect as “Reverse  Loading.”  What does this mean?  It means that you will likely find stiff wind slabs in unusual locations if you’re out and about this weekend.  The winds have been cranking & I suspect that there are a lot of Hard Slabs in the region, especially on aspects immediately lee to the recent winds, those that face south through west.  These slabs pose a real problem because of their tendency to break far above you as evidenced in last weekend’s accident (See below). 

The best strategy with this kind of avalanche problem is avoidance; stick to simple wind sheltered terrain below treeline where you will also find the best riding conditions.

Avalanche Summary

A snowmobiler was involved in an avalanche near Powder King on Sunday in what sounds like open wind exposed terrain.  He graciously reported the incident and you can read about it here: 

http://bit.ly/xRvBhq

Snowpack Summary

A test profile dug near Powder King last weekend shows three different sudden planar shears in the snow pack buried down 20 cm, 40cm & 60cm.  With these kinds of results I can infer that a wind slab avalanche could step down and trigger one of the buried persistent weak layers which would make for a large and destructive avalanche.

Weather Forecast:

A pacific frontal system will move into the region this weekend bringing clouds on Friday, moderate snow on Saturday & light snow on Sunday.  This new snow will cover the old wind slabs which may hide the real danger.  Stay alert to how the snow feels under your machine or skis.  If it feels hard, then you’re likely in the realm of the wind slab.  Be alert to what’s above you too.  Avalanches running in the new snow will likely move quickly on the faceted surface which is just one more reason why conservative terrain choices are appropriate for this weekend.

Prepared by Grant Helgeson

Next Update scheduled for Thursday January 26^th, 2012

Overview

Due to a lack of information sources, this report is mostly based on recent weather observations and information from neighboring regions. A special thanks to all the folks who have taken the time to send in their observations. Please keep it up and help us improve avalanche forecasting in the North Rockies (if you haven’t already seen it, read the post pinned to the top of this blog).

Recent strong to intense southwesterly winds combined with some new snow will have created new windslabs in the alpine, treeline and in open areas below treeline. Lingering buried winslabs are also of concern. These winds have also made cornices large and brittle. 

Avalanche Summary

There have been no new reports of avalanche activity, however there has been a lack of information sources. Keeping this in mind, I would be mostly concerned with triggeringwindslabs in the lee of terrain features in the alpine and at treeline. Considering the strength of the winds 3 days ago some of these windslabs could be found lower on slopes below traditional start zones.

 
Snowpack Summary

In snowpack tests, up to three shears may be identified in the top 80 cm of the snowpack. Reports indicate these are generally resistant in fracture quality. Earlier this week, it rained up to 1400m in some areas of the region. We have have very little information about the distribution of persistent weak layers (PWL’s) in the snowpack, such as the mid-December crust/facet/surface hoar combo or the Christmas eve surface hoar layer. One report suggests that these are less prevalent in the west of region. However if these exist they would most likely continue to be problem in steep, thin and rocky snowpack areas. 

There is a high amount of variability in the region. Snow depths in the east would be about half that of Pine Pass. With the recent strong to intense winds, I suspect windward slopes in exposed areas will be pretty scoured; deep deposits likely exist in lee areas. 

Weather Forecast

A Pacific frontal system making landfall this weekend may bring moderate to heavy amounts of precipitation. By Sunday, cold arctic air is forecast to descend upon the region bringing below seasonal temperatures and drier conditions.

Prepared by Mark Bender

Next update scheduled for Thursday Januaryy 19, 2012

Overview

The past week has been very warm, with lots of precipitation and strong winds. We don't get very many observations from this region, so a lot of the update is derived from weather station data and near neighbour information. There has been 60-100 cm of new snow in the past week combined with strong winds from the Southwest and the Northwest.

When the weather clears this weekend it may be difficult to evaluate the avalanche danger in this region. Some areas may still be producing natural avalanches, some large to very large. Some other areas may have had an obvious cycle which might show you the types of terrain where the weakness failed naturally. The third and most difficult scenario would be areas with no evidence of previous releases, or current natural avalanches. These areas may need an added trigger before they release. Be careful out there!

Avalanche Summary

I expect that the wetter areas of the region like the McGregor Range have probably already had a natural avalanche cycle on the mid-december surface hoar. Bed surfaces may re-load and slide again especially in areas where the surface hoar was sitting on a crust. The combination of strong winds and consecutive storms has probably created large new cornices that may take a while to stengthen. Drier parts of the region like the East Slope may not have reached the threshold for natural avalanches, but may be triggered by human activity.

 
Snowpack Summary

Strong winds and warm temperatures have created stiff wind slabs in the alpine and at treeline on various aspects as the wind has switched from Southwest to Northwest. Some areas have received up to a metre of new snow in the past week. Weak storm interface layers from last week are now buried 50-100 cm. Expect to find a weak layer that developed during the long dry spell in early december. This layer may have already reacted in some areas. In the nearby Cariboos, surface hoar created in early December has been very problematic and is fairly widespread. Click here to read the latest bulletin.

Some of the areas with a shallower snowpack may continue to have a weak base layer of "sugar-like" depth hoar. Avalanches that start in the storm snow may step down to this weak base layer resulting in large avalanches.

 Weather Forecast

The next system is forecast to move across the southerly parts of the province by Friday morning. The North Rockies may get an additional 5-10 cm from this storm. There is a general clearing and cooling pattern starting Friday evening or Saturday morning that looks like it will last a couple of days. The outlook beyond that is quite variable.

This report is based on limited field observations. Please email us and tell us what you are seeing: forecaster@avalanche.ca

Prepared by: Tom Riley
Next scheduled update: January 5, 2012

Overview

We have limited information from the North Rockies region. Recent observations show that weaknesses exist in the upper snowpack which are capable of producing large, destructive avalanches. Fragile cornices are also a concern. Wind has been blowing recent storm snow around, redistributing it into hard and soft wind slabs which are variable in their distribution. Expect conditions to remain potentially touchy as a weather system approaches from the west over Christmas weekend, adding extra snow and wind-loading to the equation.

Avalanche Summary

An avalanche cycle with naturally-triggered slabs up to size 2 occurred over the last few days in response to storm snow loading. Explosives testing resulted in further slab avalanches up to size 3.5 in the areas near Pine Pass and Tumbler Ridge. These were running on a storm snow instability about 60cm deep. Large sensitive cornices also fractured several metres back from the edge of ridges. Little information has come in about avalanche occurrences further south and east in the region.

 
Snowpack Summary

A recent storm deposited around 70cm of snow with strong south-west winds and mild temperatures. An instability near the base of the storm snow failed during the observed avalanches. Wind slabs exist, mostly on slopes lee to the south-west. The snowpack in the north is deep (around 2m at treeline) with a relatively well-bonded mid-pack. Lower in the snowpack, a rain crust from late November overlies a weak, sugary base in some areas. It’s possible that facets formed around this rain crust, and early December weather conditions were ripe for surface hoar growth. However, we have no recent local observations to confirm or deny that these layers are problematic. In the nearby Cariboos, surface hoar created in early December has been very problematic and is fairly widespread. Click here to read the latest bulletin.

The Northern Rockies region is extremely variable in terms of snowpack structure. It’s likely that the snowpack in the south-east (e.g. the Kakwa) is shallower and possibly more facetted than the deep snowpack areas of Pine Pass and western slopes. Expect areas of windloading in any lee terrain, especially as winds pick up again this weekend.  

 Weather Forecast

A warm front is forecast to push in to the region on Saturday evening, with light snowfall (around 5cm). On Sunday a trailing cold front should add another 10cm or so. Expect enhanced precipitation amounts on the western side of the Rockies and drier, windier conditions further east. Strong west to south-westerly winds are likely during the Christmas weekend.

This report is based on limited field observations. Please email us and tell us what you are seeing: forecaster@avalanche.ca

Thanks and Merry Christmas!

Prepared by: Penny Goddard
Next scheduled update: December 29th, 2011

Overview

We have limited information from the North Rockies region. Recent observations show that weaknesses exist in the upper snowpack which are capable of producing large, destructive avalanches. Fragile cornices are also a concern. Wind has been blowing recent storm snow around, redistributing it into hard and soft wind slabs which are variable in their distribution. Expect conditions to remain potentially touchy as a weather system approaches from the west over Christmas weekend, adding extra snow and wind-loading to the equation.

Avalanche Summary

An avalanche cycle with naturally-triggered slabs up to size 2 occurred over the last few days in response to storm snow loading. Explosives testing resulted in further slab avalanches up to size 3.5 in the areas near Pine Pass and Tumbler Ridge. These were running on a storm snow instability about 60cm deep. Large sensitive cornices also fractured several metres back from the edge of ridges. Little information has come in about avalanche occurrences further south and east in the region.

 
Snowpack Summary

A recent storm deposited around 70cm of snow with strong south-west winds and mild temperatures. An instability near the base of the storm snow failed during the observed avalanches. Wind slabs exist, mostly on slopes lee to the south-west. The snowpack in the north is deep (around 2m at treeline) with a relatively well-bonded mid-pack. Lower in the snowpack, a rain crust from late November overlies a weak, sugary base in some areas. It’s possible that facets formed around this rain crust, and early December weather conditions were ripe for surface hoar growth. However, we have no recent local observations to confirm or deny that these layers are problematic. In the nearby Cariboos, surface hoar created in early December has been very problematic and is fairly widespread. Click here to read the latest bulletin.

The Northern Rockies region is extremely variable in terms of snowpack structure. It’s likely that the snowpack in the south-east (e.g. the Kakwa) is shallower and possibly more facetted than the deep snowpack areas of Pine Pass and western slopes. Expect areas of windloading in any lee terrain, especially as winds pick up again this weekend.  

 Weather Forecast

A warm front is forecast to push in to the region on Saturday evening, with light snowfall (around 5cm). On Sunday a trailing cold front should add another 10cm or so. Expect enhanced precipitation amounts on the western side of the Rockies and drier, windier conditions further east. Strong west to south-westerly winds are likely during the Christmas weekend.

This report is based on limited field observations. Please email us and tell us what you are seeing: forecaster@avalanche.ca

Thanks and Merry Christmas!

Prepared by: Penny Goddard
Next scheduled update: December 29th, 2011

Overview

The dryspell is gradually coming to an end. With friday's weather, the avalanche scenario will also change dramatically. Natural and human-triggered avalanches are expected for the weekend. You probably haven't seen powder in a while. Be patient and resist the urge to go straight for the steep terrain.  Careful snowpack evaluation, cautious route-finding and conservative decision making will be essential.

Avalanche Summary

A few skier-triggered size 1 avalanches have been reported in the Pine Pass area. They were reported to be running in the top 15cm. The low number of reports may speak more to the lack of information rather than snow conditions. Any observations from the field are welcome and can be sent to forecaster@avalanche.ca.

 
Snowpack Summary

The region as a whole is remote and data-sparse.  Here's a quick snap-shot of what I think is happening in the Pine Pass area: The snowpack at treeline sits somewhere between 150 and 200cm. The lower and mid snowpack are, for the most part, well consolidated. What's most notable is what has happened to the snowpack during the last dry spell: The conditions were suitable for surface hoar (hoar frost) development and the cold temperatures may well have created some facetting (sugar snow) around a harder melt-freeze crust that existed near the surface during the dry spell.
Over the last few days, about 25cm of snow fell on this potentially weak interface. This is probably the layer that was reported to be reactive in the avalanche summary and is expected to increase substantially in depth and reactivity with friday's forecast weather.
We tend to receive little information from the southern potion of the North Rockies Region, especially early in the season. I suggest reading the North Columbia forecasts for the Cariboos to get a feel for what might be happening there at this time.
In conclusion, the Northern Rockies region is extremely variable in terms of snowpack structure. What you see in one area might be totally different in another. It's important to make terrain-specific observations and discuss what you're seeing/thinking with your riding partners.

 Weather Forecast

20-30cm of snow is forecast for the region on friday and saturday. The snowfall will be accompanied by moderate to strong southwest winds with freezing levels at around 800m. Expect continued windslab development and avalanche activity with this weather. Sunday's forecast is calling for clear skies, reduced wind and freezing levels at valley bottom.



If you've been out in the mountains, send an email to forecaster@avalanche.ca to let us know what you saw. All the data we get can will help with our forecasts.
It's still early in the season and it's the perfect time brush up on your skills with an avalanche safety course. Click on the "Training" tab on the website for more info.


Prepared by: Joe Lammers
Next scheduled update: December 22nd , 2011

We tend to receive little information from the field in North Rockies, especially early in the season. I suggest reading the North Columbia forecasts for the Cariboos and Monashees/Selkirks to get a feel for what might be happening in the North Rockies right now.

The danger rating from surrounding regions is   Moderate  in the alpine. A moderate rating means "heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern".

 Avalanche Summary

We have had no reports of avalanche acivity in the region. This probably speaks more to the lack of information rather than snow conditions. Any observations from the field are welcome and can be sent to forecaster@avalanche.ca.

 Snowpack Summary

The region as a whole is remote and data-sparse.  Here's a quick snap-shot of what I think is happening in the Pine Pass area: Recent westerly winds have caused west slopes to become scoured  while stiff wind slabs will probably be found on east and northeasterly slopes. Due to higher wind values, you may find them in unsuspecting areas and lower down on slopes. About 20 cms below the surface a rain crust also exists and tests have shown easy to moderate shears on this layer. The snowpack below this rain crust is said to be moist to ground. I suspect that with the cooler temperatures this moist snow has started to gain strength. Hard windslab conditions make for easy climbing on your sled, but it could also have terrible consequences. I would suspect that the better riding is lower down. You're more likely to find powder and less likely to find an avalanche-prone wind slab.

In general, the recent dry spell has given the snowpack some time to heal but avalanches are still a real possibility. Looking ahead, this dry spell has been the perfect recipe for surface hoar development and we could see a highly reactive layer come to life with the next snowfall.

In conclusion, the Northern Rockies region is extremely variable in terms of snowpack structure. What you see in one area might be totally different in another. It's important to make terrain-specific observations and discuss what you're seeing/thinking with your riding partners. It's still early in the season and it's the perfect time brush up on your skills with an avalanche safety course. Click on the "Training" tab on the website for more info.

 Weather Forecast

A ridge of high pressure will persist through friday bringing clear skies, seasonal temperatures and light northwesterly winds. On saturday, the ridge should erode as a cold front is expected to bring increased cloud, snow flurries, light westerly winds and slight warming.
On sunday the ridge should rebuild with clear skies, cooler temps and light northwesterly winds.

If you've been out in the mountains, send an email to forecaster@avalanche.ca to let us know what you saw. All the data we can will help. (Thanks to Sledder Dalton for the info this week!)

Prepared by: Joe Lammers

Next scheduled update: December 15th , 2011

There is very little information coming out of the region. However, there are a few people who have generously contributed to the content used in this report & we’re super grateful for their efforts. If you see something interesting in the field, please let us know about it. You can send observations to: forecaster@avalanche.ca

Click here for the latest North Columbia-Cariboos Avalanche Forecast. The North Columbia-Cariboos is the next door neighbour and conditions may be similar.

From The Field

High and dry conditions this week have promoted settling of all the snow the region received over the last few weeks.  Last weekend a few minor instabilities were noted in test profiles, but I suspect that a week of benign weather has allowed these to heal.    

Avalanche Summary

The sun is gaining strength as we enter mid-February.  Much of the province experienced a natural avalanche cycle last weekend as cold dry snow had its first encounter with solar radiation.  In the North Rockies the following activity was reported from last weekend & early this week:

Slab avalanche, Murray Ridge, elev: 1200 m, aspect: E aprox. 250m wide

Slab Avalanche near Powder King, elev:  1200 m, S aspect, 50cm deep x 400m wide x 150m in length

Several Slab Avalanches with approximate crown heights of 100 cm were reported from the Kakwa, occurring on E and NE aspects.

The North Rockies report covers  a very large area, and this is by no means an exhaustive list of avalanche activity.  Think of it as more of a glimpse into a cycle that was likely widespread.

Snowpack Summary

Lots of new snow the past two weeks means well above average snowpack depths. I suspect there’s 150 cm or more snow now covering the weak layers from mid-January cold snaps in deeper snowpack regions.  Operators in adjacent regions are reporting large cornices.  With continued mild temperatures forecast for the weekend, it will be important to factor cornice fall into your decision making.  It’s possible for car sized chunks of cornice to fall from ridge crests.  It’s best to give these monsters a wide berth, do your best to avoid traveling underneath them.

Weather Forecast

It looks like dry & mild weather for the foreseeable future as high pressure continues to dominate the weather pattern for much of BC and Alberta.  Trace amounts of snow are expected Saturday night, continuing into Sunday, but no significant precipitation is expected.  Daytime temps will remain mild climbing to just below freezing during the day at 1500m, dropping back down to -10 or so overnight.   Winds are expected to be light & variable.

Prepared by Grant Helgeson

Next Update Thursday February 16, 2012

We tend to receive little information from the field in North Rockies, especially early in the season. I suggest reading the North Columbia forecasts for the Cariboos and Monashees/Selkirks to get a feel for what might be happening in the North Rockies right now. There is also a post in the forecaster blog (link in the left panel here) that discusses some ideas for how to approach the mountains after the end of a stormy period.

As we head into the upcoming weekend with clearing skies, and new snow, it will make venturing out very appealing. Danger rating from surrounding regions are rated CONSIDERABLE hazard in the alpine. Considerable meaning dangerous avalanche conditions, cautious rout finding, and conservative decision making. I'd like to highlight "Human Triggered Avalanches Likely". Having such limited observations, I feel avalanche conditions could be ripe, and waiting for a trigger. It's only the beginning of December, the snowpack is young and we have a full season ahead. It's a good time of year to take an avalanche course, and gather information to help your decision making in the backcountry.

 Avalanche Summary

Reports of natural isolated slab avalanches, and sluffing up to size 1.5 occured over the past couple days. No significant avalanche cycles were noted. Looking forward strong winds are forecast and this means nasty hard wind slab (below ridges but also lower down on slopes and into the trees) will be the primary avalanche problem. 

 Snowpack Summary

Strong to extreme southwest winds from earlier in the week caused westerly slopes to become scoured, and stripped. With switching winds from the north means new wind slabs on reverse aspects. Stiff wind slabs will be found lee of ridgecrests and terrain features. You may also be surprised to find them in unsuspecting areas and lower down on slopes. The problem with hard slabs is that they're likely to release above you, when you're low on the slope. 1200m and below a rain crust from November 27th exists. The snowpack below this rain crust is said to be weak, and moist to ground. I suspect with the cooler temperatures this moist snow will start to refreeze and lock up (making it stronger).

 Weather Forecast

Light to moderate precipitation should be short lived and taper off tonight. Ridgetop winds from the NW could reach 100-135km/h overnight, then decrease Friday to 60km/h. Treeline winds will be westerly reaching 70-100km/h tonight, decreasing to 50-60km/h tomorrow. Another high pressure system is building over the province and should persist through the weekend bringing cool (seasonal) and mainly sunny conditions.

If you've been out in the mountains, send an email to forecaster@avalanche.ca to let us know what you saw. All the data we can get our hands on right now will help.

Prepared by: Shannon Werner

Next scheduled update: December 8, 2011

We have received no information from the North Rockies region since the unfortunate fatal accident of November 13. At that time, there had been a significant storm that produced storm snow and windslab problems. After that time, I suspect things settled down a bit but likely have since started up again with the onset of another series of storms. Without data, I'd be speculating to try and be specific right now.

I suggest reading the North Columbia forecasts for the Cariboos and Monashees/Selkirks to get a feel for what might be happening in the North Rockies right now. Also, I put a post in the forecaster blog (link in the left panel here) that discusses some ideas for how to approach the mountains after the end of a stormy period like the one many regions in western Canada are experiencing at the moment.

It's worth noting that most of the mountains of western Canada have been rated High danger for several days and it looks like that trend will continue for several days yet. In other regions we've seen at least two significant avalanche cycles in the last few days, with slides up to size 3 (big enough to destroy a truck) running to valley bottoms. 

It looks like the next series of storms will impact the North Rockies at least once if not twice before the end of the weekend. Given that and what's going on in other areas, I'd suggest this is a time to be very careful in the mountains up there right now. In fact, my forecasts for other regions have been recommending people stay out of avalanche terrain completely until this storm ends. Playing in non-avalanche terrain is your best bet until this all blows over. Or hunker down and sit the weekend out in front of the TV and watch the Lions take on the Bombers.

If you've been out in the mountains, send an email to forecaster@avalanche.ca to let us know what you saw. All the data we can get our hands on right now will help.

Prepared by: Karl Klassen

Next scheduled update: December 1, 2011