Avalanche Forecast

Issued: Dec 4th, 2019 4:00PM

The alpine rating is considerable, the treeline rating is moderate, and the below treeline rating is low. Known problems include Storm Slabs.

Avalanche Canada shorton, Avalanche Canada

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Human triggered avalanches remain likely in parts of the region that received more than 20 cm of snow in the recent storm.

Summary

Confidence

Moderate - Uncertainty is due to how quickly the snowpack will recover and gain strength.

Weather Forecast

WEDNESDAY NIGHT: Clearing skies overnight, light wind from the northwest, alpine temperatures drop to -8 C.

THURSDAY: Increasing cloud throughout the day, 30 km/h wind from the southwest, alpine high temperatures around -2 C.

FRIDAY: Scattered flurries bring 5-10 cm of new snow, 30-50 km/h wind from the southwest, alpine high temperatures around -1 C.

SATURDAY: Flurries continue with another 5-10 cm of snow, 40 km/h wind from the southwest, alpine high temperatures around -1 C.

Avalanche Summary

New snow and wind has formed fresh slabs that will be most reactive in wind affected terrain. Several small (size 1) human triggered slab avalanches were reported on Tuesday and Wednesday. These slabs were between 10 to 30 cm thick and occurred on all aspects.

Snowpack Summary

The past few days delivered about 15-30 cm of snow to most parts of the region, with the exception of the Kootenay Pass area that received closer to 40 cm of snow. This snow has been blown around by southwest wind and sits above hard layers of wind pressed snow and crusts. These hard layers could provide a bed surface for avalanches to slide on. The lower snowpack contains several 'sandwiched' layers of facets and crusts as well as a potential surface hoar layer (see video here). These type of layers can potentially develop into avalanche problems, but recent observations suggest they are unreactive at the moment. Snowpack depths are about 120 cm at treeline and taper quickly below treeline.

Problems

Storm Slabs

An icon showing Storm Slabs

Triggering storm slab avalanches remains a concern in steep and convex terrain, especially in areas the have more than 20 cm of fresh snow.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Dec 5th, 2019 4:00PM