Avalanche Forecast
Issued: Dec 4th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Deep Persistent Slabs.
William Lawson,
Natural avalanche activity has tapered since last weeks storm. The snowpack is still adjusting to the significant load, and considerable hazard remains at upper elevations.
Summary
Weather Forecast
A cooling trend will continue into Monday with evening lows dropping to -20 near valley bottom. Ridge winds will be light to moderate from the North West for the next few days. Light snow fall is expected overnight Saturday with accumulation amounts up to 5cm. Mix of sun and cloud forecasted for Sunday.
Snowpack Summary
The storms from last week brought up to a meter of settled snow at treeline and periods of rain as high as 2200m. Cold temps this weekend have now formed a crust near the surface below 2200m. The new storm snow now over layers the lingering Nov.15 interface and the Nov. 5 crust/facet layer found near the ground.
Avalanche Summary
Evidence of a recent widespread avalanche cycle to size 4 is evident though the forecast region. No new natural avalanche were observed today. Local ski hill reported triggering avalanches to size 2.5 with explosives.
Confidence
Problems
Storm Slabs
Soft slabs can be found at treeline and above, these continued to be reactive to explosives 50 to 100cm deep. More wind effect is evident in the alpine as is recent cornice development.
- If triggered the storm/wind slabs may step down to deeper layers resulting in large avalanches.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
Explosives continued to produce slabs on the Nov 5 crust/facets. Some slabs have initiated on this layer, while others were "step down" avalanches triggered as storm slabs or cornices failures hit them.
- Be aware of the potential for full depth avalanches due to deeply buried weak layers.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 5th, 2021 4:00PM
