Sea To Sky

Date Issued: Wed, 16 Jan 2019 23:27

Valid Until: Thu, 17 Jan 2019 22:00

Forecaster: dsaly

Avalanche hazard will increase with forecasted snowfall starting late Thursday.

Thu, 17 JanFri, 18 JanSat, 19 Jan
Alpine2 Moderate3 Considerable4 High
Treeline1 Low3 Considerable3 Considerable
Below Treeline1 Low2 Moderate3 Considerable
Confidence: Low - Intensity of incoming weather systems is uncertain on Friday
Thu, 17 JanFri, 18 JanSat, 19 Jan
Alpine2 Moderate3 Considerable4 High
Treeline1 Low3 Considerable3 Considerable
Below Treeline1 Low2 Moderate3 Considerable
Confidence: Low - Intensity of incoming weather systems is uncertain on Friday

Wind Slabs

Travel and Terrain Advice

  • Be alert to conditions that change with elevation or through the day.
  • Minimize exposure to cornices overhead and stay back on ridges.

Forecast Details

Avalanche Summary

There have been no recent avalanches reported in the region since Monday when explosives triggered small cornices and one size 2 loose-wet avalanche in the alpine around mid-day.

On Sunday, two very large (size 3) slab avalanches were reported in the region. These avalanches occurred around 1500-1900 m and two of these avalanches were observed on south-south east aspects. It is likely that that solar warming and sloughing triggered these avalanches Friday or Saturday.

On Saturday, several large cornice falls were triggered naturally and with explosives.. Some of these triggered size 2 slabs on slopes below. There is a trend of cornice falls increasing in size and frequency as the warm weather continues. Loose wet avalanches to size 2 were also failing naturally on sunny aspects on Saturday with continued reports into Sunday.

Snowpack Summary

Colder overnight temperatures are promoting better recovery of the snowpack, refrozen crusts are found on all aspects below about 1800-2000 m and sunny aspects in the alpine. These may break down with warming through the day. Cold, dry and wind-affected snow may still be found on more north-facing and polar aspects above 1700 m. Variable instabilities exist in recent storm snow layers.

Surface hoar has begun to form, and is most noticeable on shaded aspects and below tree line. While not a concern yet (and maybe really neat to ski), this potentially weak layer will not bond well with incoming snow.

Professionals continue to track two weak layers in the upper 2 m of the snowpack at and below treeline. These layers consist of surface hoar (feathery crystals) in more sheltered areas and a crust on solar aspects and on all aspects below 1600 m. In the lower snowpack, a crust/facet (sugar snow) layer is now over 2 m deep. This layer may still be reactive to heavy loads (such as a cornice fall) in isolated areas. Recent warm temperatures have promoted settlement in the midpack and there have be no recent significant results on these layers.

Weather Forecast

WEDNESDAY NIGHT: Clear periods. Freezing level valley bottom. Alpine low -6. Moderate east wind.

THURSDAY: Cloudy with isolated flurries, up to 15 cm accumulating late in the evening. Freezing level 1400 m. Alpine high near -1. Moderate southeast wind.

FRIDAY: Snow, 15-30 cm. Freezing level 1400 m. Alpine high -1. Moderate south wind with strong gusts.

SATURDAY: Heavy snow, 20-30 cm. Freezing level 1200 m. Alpine high -3. Moderate southwest wind gusting to strong to extreme.

More details can be found in the Mountain Weather Forecast.