Avalanche Forecast
Issued: Dec 12th, 2020 4:47PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Loose Dry and Deep Persistent Slabs.
Stephen Holeczi,
Watch for power sloughing of the faceted surface snow in steep terrain. Although fairly small, they can travel far and fast. Great ski quality for December.
Summary
Weather Forecast
Mainly cloudy with continued colder temperatures (-18 to -20C in the AM) with a slight increase in wind which could gust moderate above 3000m. Some flurries possible but only trace amounts. Winds will increase on Monday and especially Tuesday.
Snowpack Summary
20-40 cm of faceted snow sits on the Dec 7th layer of sun crust, facets or surface hoar depending on your location. The Nov. 5th crust / facet layer persists at the bottom of the snowpack and continues to weaken over time. Snowpack depths are 90-160cm at tree line.
Avalanche Summary
There were numerous reports of loose, dry avalanches up to sz 2 in steeper alpine features like gullies which were running far on Saturday. The theory is the 20-40cm received last week has faceted and not been exposed to any wind. Even light winds today may have initiated these. Similar types of avalanches were observed in Little Yoho.
Confidence
Problems
Loose Dry
20-40 cm of recent snow has faceted. In steep, alpine features, wind or people can start a small avalanche that will run far on the sun crust, facets or isolated surface hoar it lies on (Dec.7 layer).This trend may increase over the next few days.
- Be careful of loose dry power sluffing in steep terrain.
Aspects: All aspects.
Elevations: Alpine.
Likelihood
Expected Size
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 have only 1 observation of a deep slab avalanche since the storm, but it is still on our minds in shallow 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
Valid until: Dec 13th, 2020 4:00PM
