Avalanche Forecast
Issued: Nov 30th, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Deep Persistent Slabs.
ahanna,
Avalanche Canada
As the wind shifts northwest, watch for new wind slabs in unusual locations.
Summary
Confidence
Low - Uncertainty is due to the limited number of field observations.
Weather Forecast
Monday night: Clearing, moderate northwest wind, freezing level valley bottom.
Tuesday: Clear, light northwest wind, freezing level 500 - 1000 m with an above freezing layer developing 2500 - 3500 m in the late afternoon.
Wednesday: Clear, light southeast wind, freezing level 700 m with an above freezing layer 1500-3000 m.
Thursday: Clear, light southwest wind, freezing level 700 m.
Avalanche Summary
Explosive control work produced size 1-1.5 wind slab avalanches on Friday. We've not had any reports of avalanche activity since then.
Our eyes and ears in the mountains are limited at this time of year and may continue this winter due to fewer professional observations. If you see anything (or don't) while out in the field, please consider sharing via the Mountain Information Network (MIN). Photos are especially helpful! Thank you so much for all the great MINs submitted so far!
Snowpack Summary
Wind and small inputs of snow have formed wind slabs in on a variety of aspects at upper elevations. In more sheltered areas, recent snow may rest on a couple of layers of surface hoar 5-10 cm and 15-25 cm below the surface.
Treeline snowpack depths sit around 100 to 150 cm in the north and 50 to 100 cm in the south of the region.Â
Melt-freeze crusts from mid- and early-November are generally found 30 cm below the snow surface and 30 cm up from the ground, respectively. While they are still showing results in snowpack tests, most reports indicate that the bonds at the interfaces with these crusts are improving.
Terrain and Travel
- Be careful as you transition into wind affected terrain.
- Recent wind has varied in direction so watch for wind slabs on all aspects.
- Be aware of the possibility for full depth avalanches due to deeply buried weak layers.
- Be cautious of buried obstacles especially below treeline.
Problems
Wind Slabs
Recent wind has varied from south to northwest so watch for old and new wind slabs on a variety of aspects, especially at ridge crests and on rollovers.
Aspects: North, North East, East, South East, South, South West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
A crust exists near the base of the snowpack. A lack of decisive data on this layer is keeping it on our radar for now. While it's been showing results in snowpack tests in some areas, most reports describe an improving bond to the overlying snow. Potential for full depth avalanches may exist in areas where weak, sugary facets overly this crust, especially in areas of smooth ground cover such as scree slopes, grassy slopes, or rock slabs.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 1st, 2020 4:00PM
