Avalanche Forecast

Issued: Jan 31st, 2021 4:00PM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is low. Known problems include Wind Slabs.

Avalanche Canada ldreier, Avalanche Canada

Moderate southerly wind continues to form touchy wind slabs in lee terrain features in the alpine and exposed treeline. These slabs are particularly reactive where they overlie preserved surface hoar.

Summary

Confidence

Moderate - Uncertainty is due to the speed, direction, or duration of the wind and its effect on the snowpack.

Weather Forecast

SUNDAY NIGHT: Cloudy, 5 cm new snow, moderate southwest wind, treeline temperature -5 C.

MONDAY: Mix of sun and clouds, trace of new snow, moderate southerly wind, treeline temperature -5 C.

TUESDAY: Mainly cloudy, 5 cm new snow, moderate southerly wind, treeline temperature -8 C.

WEDNESDAY: Mainly cloudy, up to 4 cm new snow, moderate to strong westerly wind, treeline temperature -9 C.

Avalanche Summary

Several small wind slab avalanches were triggered by skiers and riders at treeline and in the alpine on various aspects on Saturday and Friday (see this MIN report). Slab avalanches up to size 2 were triggered by explosives in the north of the region over the last couple days. A few wind slab avalanches up to size 2 released naturally in the alpine on westerly aspects on Thursday. Recent glide snow avalanche activity was reported on Wednesday. 

Snowpack Summary

15-45 cm of recent snow sits on a crust below 1000 m and surface hoar in sheltered locations at and below treeline. The layers in the mid and base of the snowpack have gained strength with high snowfall amounts in January. Deeper layers appear to have gone inactive in the southern part of the region. However, in the northern part of the region (e.g. Bear Pass, Ningunsaw) there has still been regular avalanche activity on weak snow at the bottom of the snowpack with large loads such as explosives or cornice collapses.

Terrain and Travel

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.
  • Watch your sluff: it may run faster and further than you expect.

Problems

Wind Slabs

An icon showing Wind Slabs

Moderate southerly wind continues to redistribute the new snow and build fresh wind slabs in lee terrain features in the alpine and exposed treeline. Older wind slabs were formed on westerly aspects and may still be reactive. Wind slabs will be particularly reactive anywhere snow overlies buried surface hoar or crust. The surface hoar layer is likely preserved in sheltered areas at and below treeline.

In steep and wind-protected areas loose dry snow avalanches (sluffs) are expected. 

Aspects: North, North East, East, South East, West, North West.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2.5

Valid until: Feb 1st, 2021 4:00PM