Avalanche Forecast
Issued: Dec 10th, 2020 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.
Stephen Holeczi,
The new snow so far has been less reactive than we thought. Of note, small avalanches may run far if initiated due to the Dec 7 layer, especially as the new snow starts to facet. Good ski quality!
Summary
Weather Forecast
High pressure will continue Friday with light winds, and no snow. Temperatures will continue to stay cool in the valley bottoms and in the alpine (-15C)
Snowpack Summary
20-40 cm of low density new snow sits on the december 7th layer of sun crust, facets or surface hoar depending on your location. This new snow came with minimal wind and seems less reactive than we had thought it might be. At the bottom of the snowpack, the Nov. 5th crust / facet layer persists. Snowpack depths are 90-150 at treeline.
Avalanche Summary
We had good visibility in the alpine the last 2 days with field trips and the road patrols of 93S and the TCH Yoho. Sunshine reported a few wind slabs triggered in steep terrain in the new storm snow running on the Dec 7 layer. Although not large, it has been noted that they have been running far.
Confidence
Due to the number and quality of field observations
Problems
Deep Persistent Slabs
The Nov 5 crust has facets above and below it, and exists up to 2500m on shady aspects and higher on solar aspects. We haven't seen any activity on this layer since the storm, but the new load may have made it more reactive in some areas.
- Pay attention to overhead hazards like cornices which could trigger the deep persistent slab.
- Be aware of thin areas that may propogate to deeper instabilites.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Wind Slabs
It didn't seem like much wind came with this last storm, but small wind slabs have been reported over the Dec 7 layer near ridge crests in steep alpine features.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 11th, 2020 4:00PM
