Avalanche Forecast
Issued: Feb 21st, 2024 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Persistent Slabs.
cgarritty,
Avalanche Canada
Seek out soft, sheltered snow for the best quality, safest riding. A wind slab in motion could step down to a deeper weak layer and become surprisingly destructive.
Summary
Confidence
Moderate
Avalanche Summary
Over the past week we've seen a pattern of human and remotely triggered, mainly size 1 to 1.5 wind slab avalanches. These avalanches have generally failed on a combination of facets and/or surface hoar sitting on hard crust. Check out this MIN for a recent snapshot of the issue.
Although new snow is shifting some focus away from this older problem, it isn't off the radar. It is adjusting to a new load and the possibility for surface avalanches to trigger it can't yet be ruled out.
Snowpack Summary
15 - 20 cm of new snow from the early art of the week has buried over a variety of previous surfaces including; a crust on south aspects and all aspects at lower elevation, surface hoar in sheltered features, and previously wind-affected surfaces in the open.
Roughly 40 - 50 cm of snow now sits above a widespread crust from late January. Weak grains like facets or more isolated surface hoar may be found above this crust. Old wind slabs that formed above this weak snow remain a concern. Will we see surface wind slabs stepping down to this layer to create larger avalanches?
Snowpack depths decrease rapidly below treeline.
Weather Summary
Wednesday night
Cloudy with isolated flurries. 5 to 10 km/h south alpine wind. Freezing level around 1500 m.
Thursday
Cloudy with isolated flurries. 5 to 15 km/h southwest alpine wind. Treeline temperature around 0 °C with freezing level rising to 1700 m.
Friday
Mainly cloudy with isolated flurries, increasing a bit overnight. 15 to 30 km/h southwest alpine wind. Treeline temperature -2°C with freezing level around 1500 m.
Saturday
Cloudy with scattered flurries bringing less than 5 cm of new snow, including overnight amounts. 15 to 25 km/h southwest alpine wind. Treeline temperature -2 °C with freezing level to 1500 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Wind slabs are most reactive during their formation.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
Problems
Wind Slabs
Slab formation in our new snow will be most pronounced near ridges and in the lee of exposed terrain features. Slabs that form likely won't bond well to the old surface.
Aspects: North, North East, East, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
New snow has been adding to the load over weak layers from early February. Smaller surface avalanches may have potential to step down to this layer to create a larger, more destructive avalanche.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 22nd, 2024 4:00PM
