| Monday | Tuesday | Wednesday | |
|---|---|---|---|
| Alpine | 4 High | 4 High | 4 High |
| At Treeline | 4 High | 4 High | 4 High |
| Below Treeline | 3 Considerable | 3 Considerable | 3 Considerable |
| Monday | Tuesday | Wednesday | |
|---|---|---|---|
| Alpine | 3 Considerable | 3 Considerable | 3 Considerable |
| At Treeline | 3 Considerable | 3 Considerable | 3 Considerable |
| Below Treeline | 2 Moderate | 2 Moderate | 2 Moderate |
The orange segments show which aspects are most affected by the primary concern. If the icon is completely orange, this means the primary concern exists on all slopes.
Alpine, Treeline and Below Treeline are separate zones with distinct characteristics. The arrow points to the zones most affected by the primary concern. For more information on elevation zones, click here.
Indicates the time of day where the primary concern is likely to be a problem. Avalanche conditions can change between shady, cool mornings and sunny, warm afternoons. If both icons appear, it means the primary concern is present all day.
In coastal areas up to 80 cm accumulated with the last storm, this one should be similar. Less for inland areas but lots of wind there - see windslab concern below.
The orange segments show which aspects are most affected by the primary concern. If the icon is completely orange, this means the primary concern exists on all slopes.
Alpine, Treeline and Below Treeline are separate zones with distinct characteristics. The arrow points to the zones most affected by the primary concern. For more information on elevation zones, click here.
Indicates the time of day where the primary concern is likely to be a problem. Avalanche conditions can change between shady, cool mornings and sunny, warm afternoons. If both icons appear, it means the primary concern is present all day.
Strong Southerly winds mean the storm snow is being concetrated on lee northerly facing slopes and behind wind-break features on cross loaded terrain. Likely widespread in alpine areas and in open treeline areas, especially below ridges.
Time to pull in the reins, and play conservatively. The take home message is avoid avalanche terrain unless you have professional level training & experience. Pros are choosing their terrain carefully to minimize the size and consequences of any avalanches they might encounter.
Boulder Mountain Avalanche Incident Revelstoke B.C. Saturday March 13, 2010 3pm. Slab, size 2.5 – 3, incline: “steep,” NE aspect, low Alpine feature (~2300m), main section that affected the people involved ~300m wide, significantly more fracture line wraps around shoulder, perhaps another 300m, linear run about 700m including running over a bench at about 2000m then down a steep slope below to edge of mature timber. Depth of debris up to 3m. Two fatalities, 19 hospitalized (1 critical, 3 serious). Tens of sleds destroyed or seriously damaged. Rescue winding down. Miracle that no more people were killed or injured. See RCMP press release.
Good for Coastal areas, Fair for Inland Sections due to limited data.
I expect that by Monday morning there’ll be 80 to 100cm of new snow (since Saturday afternoon) in Coastal areas and upwards of 30 cm for inland areas. Strong S’ly winds accompanied this storm. Monday: Precipitation winding down with an additional 5 to 15 cm possible, some of it arriving in localized convective bursts. Freezing level near 900 m. Mod to Strong S’ly winds. Tuesday & Wednesday: The next wintery storm is forecast to affect the region with light to moderate precipitation, southerly winds, and moderate S’ly winds. Yup, it took until March for January weather to arrive!
Numerous reports of large (up to size 4) natural and ski/sled triggered avalanches throughout the region on Friday and Saturday with the last storm. Check out the Skeena/Babine discussion forum for great photos and information. Sunday’s storm is packing a stronger punch so similar natural cycle of large avalanches is expected for Terrace and Coastal areas. Despite less precipitation, I suspect inland sections (where we have less data) will also see a widespread avalanche cycle on wind-loaded lee slopes. In most areas rider-triggered avalanches are “very likely” or “almost certain” the next few days.
It’s the first time this winter we’ve seen back-to-back winter storms. They’re falling on a somewhat unusual snowpack and it’s being shocked. The last storm created large avalanches and there’s no reason to think otherwise now.
Terrrain to Avoid: overhead hazard especially N’ly facing alpine slopes & cornices, avoid terrain traps that could lead to deep burial, carry you over a cliff, or through trees.
Ideas to Manage Risk: Stick to non-avalanche terrain or small features with limited consequence. View the mountains with an eye for the unexpected event that's larger than you’ve seen or in places where you haven't seen an avalanche before. Watch for signs of unstable snow like whumpfing, shooting cracks, or recent slides. If observed, back off to lower angle terrain.
Very strong southerly winds have created widespread deep wind slabs well below ridge crests throughout alpine areas and open treeline areas. Normally I’d consider the PWLs (i.e. Feb 28 alpine surface hoar on E, N, and W primarily shady slopes) too deeply buried to worry about; however, they were a player in last week’s avalanche cycle so don’t discard them quite yet.
Snowfall amounts are significantly less inland, but winds have been strong. Pockets of wind slab exist in lee and cross-loaded terrain.
Prepared by ilya storm & pm
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Recent avalanche incidents for this region. To view all reported incidents please check out the discussion forum:
