Avalanche Forecast
Issued: Dec 5th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
wlewis,
Avalanche Canada
Recent snowfall is bonding poorly with the underlying crust. Avalanches will move fast on this surface. Be cautious in steep terrain above cliffs and terrain traps, and in wind loaded features.
Summary
Confidence
Weather Forecast
SUNDAY NIGHT: Partly cloudy with moderate westerlies. Freezing levels at valley bottom.
MONDAY: Cloudy with flurries, up to 5 cm of accumulation. Moderate to strong westerly winds. Freezing levels at valley bottom. Alpine highs of -8.
TUESDAY: Partially cloudy with isolated flurries. Strong northwest winds at ridgetop, freezing levels at valley bottom. Alpine highs of -12.
WEDNESDAY: Snow returns Tuesday night with moderate accumulations. Freezing levels rise to 1000m.
Avalanche Summary
Yesterday, small loose dry avalanches were observed out of steep sheltered terrain features. Size 1-1.5 wind slab avalanches were observed in immediate lee features at ridge crest.
Note there are very few field observations this early in the season. If you head out this weekend, please share your observations and/or photos on the Mountain Information Network!
Snowpack Summary
15-30 cm of new snow sits on top of a thick rain crust on all aspects below 2400m. Westerly winds will continue to redistribute this new snow into wind slabs in the alpine and treeline.
Previously, the mid-November rain crust could be found 20-30 cm above the ground. It is likely heavy rain has begun to break down this crust at treeline and below, and created a cohesive refrozen snowpack with the thick rain crust at the surface.
Snowpack depths range from 10-80 cm at treeline elevations. Higher elevations may hold a deeper snowpack, but will also be more heavily impacted by recent winds. Rain has washed away the snowpack below 1900m.
Terrain and Travel
- Be careful as you transition into wind affected terrain.
- Wind slabs may be poorly bonded to the underlying crust.
- Be aware of the potential for loose avalanches in steep terrain where snow hasn't formed a slab.
Problems
Wind Slabs
Strong westerly winds will continue to build wind slabs in the alpine and treeline. Approach ridge crest and wind loaded features with caution. These wind slabs will be most reactive to human triggering where they overlie a thick, smooth rain crust.
Aspects: North, North East, East, South East, South, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 6th, 2021 4:00PM
