Avalanche Forecast
Issued: Dec 7th, 2020 4:19PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs, Persistent Slabs and Loose Dry.
Jeff Andrews,
The storm continues with up to 30cm in the forecast. Expect rolling closures on Hwy 93 for avalanche control.
The new snow is welcome but conditions are perfect for sensitive wind slabs to develop in exposed terrain.
Summary
Weather Forecast
The tail of a strong Pacific frontal system will bring moderate precipitation (up to 25mm) overnight through tomorrow morning accompanied by moderate to strong ridge top winds from the southwest. A cooling trend is expected Wednesday.
Snowpack Summary
5cm new snow today with strong SW ridge winds burying a variety of surfaces including facets and isolated surface hoar TL and BTL, hard slab in the alpine and open TL, and solar crust on steep solar. Snow depth at tree line is up to 95cm with the Nov 4 crust down 50cm. Basal weakness continue to develop. An additional 25cm is expected overnight.
Avalanche Summary
No avalanches observed or reported today. No road patrols today. Expecting an avalanche cycle tomorrow with the up to 30mm in the forecast overnight.
Confidence
Problems
Wind Slabs
Storm snow coming in with strong SW winds - may see more reactivity at treeline where new slabs are building on a weak facet layer.
- If triggered the wind slabs may step down to deeper layers resulting in larger avalanches.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
The Nov. 4 crust is down about 50cm at tree line (2000m) and breaking down. Wind slabs may step down to this layer or even deeper to the basal instability creating large destructive avalanches.
- Be cautious in shallow snowpack areas where triggering is more likely.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Loose Dry
- Avoid terrain traps, such as gullies, where the consequences of a small avalanche could be serious.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Dec 8th, 2020 4:00PM
