Avalanche Forecast
Issued: Dec 8th, 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
Strong winds have stripped away new snow to the icy crust in exposed terrain. Expect pockets of wind slab to remain reactive where they sit on the problematic crust.
Seek out sheltered low angle terrain for the best riding.
Summary
Confidence
High - We have a good understanding of the snowpack structure and confidence in the weather forecast
Weather Forecast
Snowfall tapers as the front exits today, replaced by scattered flurries and mixed cloud until a juicer system approaches this weekend.
WEDNESDAY NIGHT: Flurries continue with moderate west-southwest winds. Freezing levels drop to valley bottom.Â
THURSDAY: Cloudy with a chance of flurries, light westerlies. Freezing levels at valley bottom. Alpine highs of -8.Â
FRIDAY: Trace amounts of snow, most cloudy. Freezing level at valley bottom, alpine highs of -8. Light westerlies.Â
SATURDAY: Light to moderate snowfall starts early Saturday morning. Freezing levels climb to 1500m. Alpine highs of -3. Strong to extreme southwest winds.Â
Avalanche Summary
Explosive control work in the south produced a size 1.5 wind slab failing on a melt freeze crust.
Nearby in the Lizard-Flathead area, a size 2 natural wind slab was observed on Tuesday.Â
Several other skier triggered and natural loose dry avalanches have been observed over the last 4 days.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
Up to 20cm of snowfall has fallen on a thick and thick and supportive crust, on all aspects below 2400m. Westerly winds have redistributed this into lee features in the alpine and treeline. In exposed alpine and treeline areas, the wind may have stripped the snow back to the crust making for hazardous travel conditions.Â
The snowpack holds several early season crusts about 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
- Watch for wind-loaded pockets especially around ridgecrest and in extreme terrain.
- Wind slabs may be poorly bonded to the underlying crust.
- Choose low-angled, sheltered terrain where new snow hasn't been wind-affected.
Problems
Wind Slabs
Pockets of wind slab still remain 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.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 9th, 2021 4:00PM
