Avalanche Forecast
Issued: Dec 7th, 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 snow will be most reactive where it sits on the icy crust. Expect wind loading at ridge crest and in cross loaded terrain. Keep your head up - variable winds may have loaded unexpected features.
Summary
Confidence
High - We have a good understanding of the snowpack structure and confidence in the weather forecast
Weather Forecast
A cold front brings snow and strong winds overnight. Wednesday afternoon will see clearing skies and calmer conditions as the front moves out, replaced by a weak high pressure system.
TUESDAY NIGHT: Light snow beginning overnight, up to 3cm by Wednesday morning. Strong southwest winds, freezing levels at valley bottom.Â
WEDNESDAY: Snow continues with 2-10cm over the day. Winds increase to extreme south westerlies. Freezing levels rise to 1500m, alpine highs of -3.Â
THURSDAY: Flurries continue, with light westerlies. Freezing levels below 500m. Alpine highs of -9.Â
FRIDAY: Cloudy skies with a chance of flurries. Light westerly winds. Alpine high of -9.
Avalanche Summary
Nearby in the Lizard-Flathead area, numerous skier triggered and natural wind slab (to size 2) and loose dry (to size 1) avalanches have been observed over the last 3 days.Â
On Sunday, 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.Â
Note there are very few field observations this early in the season. If you venture out into the mountains, please share your observations and/or photos on the Mountain Information Network!
Snowpack Summary
15-30cm of low density snowfall sits over a thick and supportive crust, on all aspects below 2400m. Moderate to strong westerly winds continue to redistribute this new snow into deeper deposits in lee features in the alpine and treeline.Â
The mid November crusts sit 20-40cm above the ground below 2300m. Last week's heavy rain saturated the snowpack and has begun to break down this crust at treeline and below, creating a cohesive lower snowpack.
Snowpack depths range from 10-80 cm at treeline elevations. The snowpack tapers quickly below 1900m, significantly diminished by the rain event.
Terrain and Travel
- Keep in mind the crust offers an excellent bed surface for avalanches.
- Wind slabs may be poorly bonded to the underlying crust.
- Avoid slopes that sound hollow or drum-like.
Problems
Wind Slabs
Strong westerly winds and snow throughout the day will continue to build wind slabs in the alpine and treeline. Approach ridge crest and wind loaded features with caution, variable wind directions may create reverse loading patterns. 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, South West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 8th, 2021 4:00PM
