Avalanche Forecast
Issued: Dec 9th, 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
Watch for pockets of wind effected snow near ridgelines, and loading in unexpected features. The icy crust continues to make for hazardous travel conditions in exposed areas. Check out low angle, sheltered terrain for the best riding conditions.
Summary
Confidence
High - We have a good understanding of the snowpack structure and confidence in the weather forecast
Weather Forecast
A front pushes through the interior on Saturday bringing warmer weather, moderate to heavy snowfall and very strong ridgeline winds.
THURSDAY NIGHT: Cloudy with flurries overnight, light southwest winds. Freezing levels at valley bottom.Â
FRIDAY: Mostly cloudy with flurries. Freezing level at valley bottom, alpine highs of -8. Moderate south-westerlies. Snow begins overnight, up to 5cm expected by Saturday morning.Â
SATURDAY: Snowfall increasing throughout the day, delivering 10-15cm and another 5cm possible overnight. Freezing levels climb to 1500m. Strong to extreme southwest winds.Â
SUNDAY: Light snowfall continues, with 5cm expected over the day. Winds ease back to moderate southwesterlies.
Avalanche Summary
Explosive control work in the past two days has produced multiple wind slabs to size 1.5, running on the most recent melt freeze.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
Strong to extreme westerly winds have stripped exposed terrain in the treeline and alpine, to the thick and smooth melt freeze crust or to rock. In sheltered features, the wind has redistributed snow into wind loaded pockets of over 50cm.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 30-110 cm at treeline elevations. The snowpack tapers quickly below 1900m.
Terrain and Travel
- Wind slabs may be poorly bonded to the underlying crust.
- Although their spatial distribution is isolated, wind slabs are reactive.
- 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, where they sit over an icy crust. Approach ridge crest and wind loaded features with caution, variable wind over the last week has loaded unusual features.
Aspects: North, North East, East, South East, South, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 10th, 2021 4:00PM
