Avalanche Forecast

Issued: Nov 24th, 2021 4:00PM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is moderate. Known problems include Storm Slabs.

Avalanche Canada jfloyer, Avalanche Canada

Email

Avalanche hazard will rise with an incoming winter storm on Thursday. I'm expecting most areas to see around 25 cm of new snow by the end of Thursday. If storm amounts build up to 35 cm or more, consider the alpine and treeline avalanche danger to be high.

Summary

Confidence

Moderate - Uncertainty is due to the track & intensity of the incoming weather system.

Weather Forecast

Wednesday night: Around 10 cm new snow. Strong Southwesterly ridgetop winds.

Thursday: 15-20 cm new snow. Freezing levels rising to approximately 1400 m in the afternoon. Moderate 

southwesterly winds at treeline elevations, strong or extreme southwesterly winds at ridgetop.

Friday: Around 10 cm new snow. Freezing level around 1400 m. Strong southwesterly ridgetop winds.

Saturday: Some clear spells in the morning. Around 5 cm new snow in the afternoon. Freezing levels at valley bottom. Moderate southwesterly ridgetop winds.

Avalanche Summary

Recent size 1.5-2 wind slab avalanches have been reported from exposed locations at higher elevations (above approximately 2000 m) on various aspects.

Expect avalanche activity to increase as the storm builds through the day on Thursday.

Snowpack Summary

20-50 cm of recent snow sits above a rain crust from mid-November. This rain crust exists at elevations to at least 1800 m and potentially up to 2100 m. The wind has moved the recent snow into wind deposits in exposed alpine areas.

Terrain and Travel

  • Watch for changing conditions today, storm slabs may become increasingly reactive.
  • Dial back your terrain choices if you are seeing more than 20 cm of new snow.
  • Avoid lee and cross loaded slopes in the alpine.

Problems

Storm Slabs

An icon showing Storm Slabs

Natural avalanches are likely to start running on steep slopes when accumulations reach approximately 35 cm of new snow. On windy slopes, this threshold will be reached much sooner and their dense nature will make them easier to trigger.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

1.5 - 2.5

Valid until: Nov 25th, 2021 4:00PM