Avalanche Forecast
Issued: Dec 6th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Deep Persistent Slabs and Wind Slabs.
Lisa Paulson,
The current avalanche hazard fits the definition of Moderate, however our main concern is with full depth avalanches failing on the basal facets which could result in high consequences if triggered. Thinner snowpack areas seem the most problematic.
Summary
Weather Forecast
Expect slightly warmer temperatures tonight and Tuesday with highs around -7C, isolated flurries, and moderate W ridge winds. No significant snow amounts for tomorrow, maybe up to 10 cm for Wednesday. See Avalanche Canada weather forecast for more details.
Snowpack Summary
Last weeks storms brought up to a meter of settled snow at higher elevations with wind effect in open areas. Periods of rain as high as 2200 m formed a crust which is down 5-30 cm depending on elevation. The lingering Nov 15 interface is down 50-100+ cm and the Nov 5 crust/facet layer is found near the ground. 90-200 cm of snow at treeline.
Avalanche Summary
No new natural avalanches were observed today. On Sunday, one significant skier accidental size 3 with a sympathetic size 2+ avalanche was triggered on Lipalian Mtn failing on the basal facets. This thinner snowpack area with variable snow depths, cross loading by the wind and steep rolls is the type of terrain we are concerned with at this time.
Confidence
Due to the number and quality of field observations
Problems
Deep Persistent Slabs
We continue to see occasional high consequence avalanches on the Nov 5 crust/basal facets in specific terrain features. Some slabs have initiated on this layer, while others were "step down" avalanches triggered as wind slabs or cornices hit them.
- Be aware of the potential for full depth avalanches due to deeply buried weak layers.
- Avoid steep convexities or areas with a thin or variable snowpack.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Wind Slabs
Wind slabs can be found in exposed treeline and alpine areas. These have not been as reactive over the last couple days but are worth paying attention to in steep lee or cross loaded features.
- If triggered the storm/wind slabs may step down to deeper layers resulting in large avalanches.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 7th, 2021 4:00PM
