Avalanche Forecast
Issued: Dec 6th, 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
Wind affected and loose snow have bonded poorly with the rain crust. Approach wind loaded features like ridge crests with caution, and manage your exposure to terrain traps in sheltered terrain where loose snow could run faster and further than expected.
Summary
Confidence
High - We have a good understanding of the snowpack structure and confidence in the weather forecast
Weather Forecast
MONDAY NIGHT: Cloudy overnight with flurries possible. Moderate westerly winds. Freezing levels at valley bottom.
TUESDAY: Partly cloudy with no snowfall expected. Strong northwest winds, freezing levels at valley bottom. Alpine highs of -9.Â
WEDNESDAY: Snow returns Tuesday night with up to 10cm expected by Wednesday afternoon. Winds increase to strong westerlies. Freezing levels rise to 1000m, alpine highs of -5.Â
THURSDAY: Light snowfall continues, with light westerlies. Freezing levels below 500m.
Avalanche Summary
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
Small avalanches will move quickly on the crust bed surface. Be mindful of what is below you, such as cliffs and gullies, especially in steep terrain.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.
- Be aware of the potential for loose avalanches in steep terrain where snow hasn't formed a slab.
Problems
Wind Slabs
Westerly winds 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 7th, 2021 4:00PM
