Avalanche Forecast
Issued: Dec 25th, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs and Wind Slabs.
ahanna,
Avalanche Canada
The snowpack is taking time to equilibrate to the snow load added earlier this week. We're being patient and sticking to conservative terrain for the next while until we have clear evidence that buried weak layers have stabilized.
Summary
Confidence
Moderate -
Weather Forecast
Friday night: 5-10 cm new snow, light to moderate southwest wind, freezing level valley bottom.
Saturday: Up to 5 cm new snow, moderate southwest wind, alpine temperature -8 C, freezing level 500 m.
Sunday: Clearing, light northwest wind, alpine temperature -4 C, freezing level 700 m.
Monday: Sunny, light northwest wind, alpine temperature -5 C, freezing level 500 m.
Avalanche Summary
Many storm and persistent slab avalanches have been observed this week across the region. They were generally large (size 2), on west, north, and east aspects, 20 to 70 cm thick, and between 2000 and 2300 m. The likelihood of triggering the buried weak layers described in the snowpack summary remains.
Snowpack Summary
A hefty storm impacted the region Monday, with around 30 to 40 cm of snow accumulation. Strong wind accompanied the storm, blowing from variable directions. Expect to find storm and wind slabs across the region until they bond to the snowpack.Â
This snow is loading two weak layers around 50 to 100 cm deep. The layers are composed of feathery surface hoar and sugary faceted grains and they overly a hard melt-freeze crust. There has already been substantial avalanche activity on this layer from natural and human triggers. This layer remains a major concern, as humans may be able to trigger large and destructive avalanches on it. There has been less avalanche activity reported west of Castlegar but a similar snowpack exists so the possibility remains.
Another crust with associated faceted grains may be found near the base of the snowpack. There haven't been recent avalanches reported on this layer but it remains on our radar. The most likely place to trigger it would be from shallow, rocky terrain.Â
Terrain and Travel
- Make conservative terrain choices and avoid overhead hazard.
- Fresh snow rests on a problematic persistent slab, don't let good riding lure you into complacency.
- Give the new snow time to settle and stabilize before pushing into bigger terrain.
- Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
Problems
Persistent Slabs
Weak layers of surface hoar and/or faceted grains overly a hard melt-freeze crust around 50 to 100 cm deep. Loading from recent storms have pushed the persistent slab problem over the tipping point resulting in large avalanches in the past week. We're being patient and sticking to conservative terrain for the next while until we have clear evidence that buried weak layers have stabilized.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Wind Slabs
Wind slabs may be found on a variety of aspects due to shifting wind directions.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 26th, 2020 4:00PM
