Avalanche Forecast
Issued: Dec 11th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Persistent Slabs.
ghelgeson,
Avalanche Canada
Southwest wind has combined with 40 to 100 cm of snow over the last few days, although the storm is tapering off, natural avalanches remain possible. Avoid wind exposed terrain and terrain traps Sunday as the storm snow continues to settle and stabilize.
Summary
Confidence
Low - Uncertainty is due to the limited number of field observations.
Weather Forecast
We’re slowly moving into a period of high pressure.
SATURDAY NIGHT: A few cm of snow overnight with moderate southwest wind, freezing level at valley bottom.
SUNDAY: Broken cloud cover, freezing level at valley bottom, light to moderate wind generally out of the south, 1 to 5 cm of snow possible.
MONDAY: Scattered cloud cover, freezing level at valley bottom, moderate to strong east/southeast wind, no significant precipitation expected.
TUESDAY: Clear skies at dawn with cloud cover increasing after lunch, freezing level at valley bottom, light southwest wind, no significant precipitation expected.
Avalanche Summary
Recent observations are limited, but there was quite a bit of avalanche activity in the storm snow on Friday, with soft slabs and dry loose avalanches running naturally to size 2.Â
If you do head into the backcountry, please share you observations to the Mountain Information Network!
Snowpack Summary
Between Friday at noon and Saturday late afternoon there has been 20 to 35 cm of new snow across the southern half of the region, and 15 to 20 in the North around Bear Pass. This brings total storm accumulations across the region to betweeh 40 and 100+ cm over the last few days. Strong southwest wind has no doubt formed fresh + potentially sensitive slabs in wind exposed terrain.
There is still some concern for buried weak layers, will the possibility for buried surface hoar and faceting above the December 1st crust, now buried 40-120 cm deep. In the southern part of the region the December 1st crust has been reported up to 2000 m, tapering to 500 m in the northern reaches. The Terrace area has reported the crust to around 1200 m.
Snowpack depths range from 150 cm- 300 cm at treeline and 200 cm- 400 cm in the alpine.
Terrain and Travel
- Give the new snow time to settle and stabilize before pushing into bigger terrain.
- Be aware of the potential for large, avalanches due to the presence of buried crust/facet combo.
- Back off if you encounter whumpfing, hollow sounds, or shooting cracks.
Problems
Storm Slabs
40-100 cm of new snow has fallen in the past three days accompanied by southwest wind which will continue to blow with enough gusto to form fresh slabs Sunday. Although snowfall is tapering, the snowpack will need time to adjust to this new load.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
There is still some concern that persistent weak layers like facets and surface hoar rest on the crust from early December, which is now down 60 to 120 cm below the surface. While the likelihood of triggering an avalanche this deep is decreasing as we move into a cooling trend after the storm, we don't have enough information to rule this out as a potential player.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Dec 12th, 2021 4:00PM
