Avalanche Forecast
Issued: Dec 11th, 2020 8:03AM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs and Deep Persistent Slabs.
Mike Smallwood,
The recent storm snow has settled and started to bond but the variability of the persistent layer below means testing is needed before committing to a line
Summary
Weather Forecast
No new snow today, cloudy skies may clear in the afternoon while winds stay calm. Freezing level is due to rise to 1000m. Tomorrow will be similar with a bit more cloud, possible flurries and winds picking up from the west in the evening. Sunday night more snow is forecast with winds shifting to the SW
Snowpack Summary
30cm of storm snow buried a variety of surfaces on Monday; surface hoar up to 10mm is rounding in some areas, localized freezing rain formed a crust in others while sunny breaks formed a crust on steeper solar aspects. Below that several surface hoar crust layers exist in the upper snowpack and the Nov 5 crust is down between 1m and 1.5m
Avalanche Summary
Tuesday's storm brought a widespread avalanche cycle to all aspects and elevations. Avalanche control Tuesday gave results to size 3.5. Numerous loose dry avalanches released yesterday when the sun came out to sz 1.5 as well as 2 sz 2s in the highway corridor from N and S aspects
Confidence
Problems
Persistent Slabs
The Dec 7 persistent weak layer of surface hoar and crusts is down between 20 and 35cm. This is still reactive in tests and 2 natural size 2 avalanches were observed yesterday
- Caution on open slopes and convex rolls at treeline and below, buried surface hoar may be preserved.
- Persistent slabs may be more sensitive to human triggering on solar asp where it sits on sun crust
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Deep Persistent Slabs
The Nov 5 crust layer is down over 1m, it is still of concern in shallow snowpack areas
- Dig down to find and test weak layers before committing to a line.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 12th, 2020 8:00AM
