Avalanche Forecast
Issued: Dec 26th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Persistent Slabs.
dsaly,
Avalanche Canada
Watch for reactive deposits in wind-loaded areas. Be ready for the cold.
Summary
Confidence
Moderate - Uncertainty is due to the limited number of field observations.
Weather Forecast
Sunday night: Cloudy with isolated flurries, up to 5 cm. Light to moderate southeast wind. Overnight temperature dropping below -32.
Monday: Cold and cloudy with sunny breaks. Gusty moderate southwest wind and cold temperatures with a high of -21.
Tuesday: Mostly cloudy with isolated flurries. Light, gusty winds and cold temperatures with a high of -22.
Wednesday: Sunny, but still cold and also windy. Gusty southwest wind and cold temperatures with a high of -20.
Avalanche Summary
On Friday, a small (size 1) storm slab was triggered by skier traffic. Riders also reported loose-dry sluffing with the new snow.
On Thursday, explosives triggered a few small (size 1) storm slab avalanches. On Wednesday, the South Rockies field team reported several wind slabs that appeared to have slid on the early December crust and up to size 2.Â
Snowpack Summary
Recent storm totals reached over 120 cm! Cold temperatures and calm wind will keep snow light and fluffy, but snow will be redistributed easily with any wind.Â
Gusty winds have produced variable storm slabs and cross-loaded terrain features. In some wind exposed areas surfaces have likely been stripped back down to older wind slabs and the early December crust. Sheltered areas may still hold loose snow. A lot of variability exists.
A crust from early December is now 60-100 cm below the surface, and is found up to 2400 m. A layer of weak facets (sugary snow) has been reported above and below this crust. This is the layer of concern in our persistent avalanche problem, snowpack tests are generally showing hard results on this interface, however, areas where avalanches have recently failed on this crust continue to be problematic once reloaded with new snow.Â
Below 2300 m, several early-season crusts make up the lower snowpack. Snowpack depths range from 80-150 cm at treeline elevations and taper quickly below 1900m.
Terrain and Travel
- Start with conservative lines and watch for clues of instability.
- Fresh wind slabs will likely form throughout the day, diligently watch for changing conditions.
- Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
- Be aware of the potential for large avalanches due to the presence of a persistent slab.
Problems
Wind Slabs
Wind will quickly redistribute any loose snow. Recent winds have been north and easterly, be mindful of reverse loaded features. Watch your sluff, loose-dry snow may easily initiate in steep terrain.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
A layer of weak facets (sugary snow) can be found down 60-100 cm over a crust that formed in early December. This layer has produced large avalanches with explosive triggers and has shown reactivity in snowpack tests. A larger trigger such as a skier or snowmobile, may add enough stress to trigger a persistent slab.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Dec 27th, 2021 4:00PM
