Avalanche Forecast

Issued: Dec 6th, 2019 4:00PM

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

Avalanche Canada ldreier, Avalanche Canada

Gather information as you approach avalanche terrain, there is uncertainty about how quickly the recent storm snow is gaining strength.

Summary

Confidence

Moderate - Uncertainty is due to how the snowpack will react to the forecast weather.

Weather Forecast

FRIDAY NIGHT: Cloudy with isolated flurries, up to 30 km/h gust winds from the southwest, alpine temperatures around -2 C, freezing level around 900 m.

SATURDAY: Flurries continue with another 5-10 cm of snow, up to 30 km/h gust winds from the southwest, alpine high temperatures around -2 C, freezing level at 1400 m.

SUNDAY: Cloudy in the morning then clearing in the afternoon, 40 km/h wind from the northwest, alpine high temperatures around -4 C, freezing level at 1000 m.

MONDAY: A few clouds, no precipitation, 40 km/h wind from the northwest, alpine high temperatures around -5 C, freezing level at 900 m.

Avalanche Summary

Recent snow and wind has formed 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. A small natural point release (size 1) was observed in a steep eastern aspect at treeline.

Snowpack Summary

The past few days delivered about 15-40 cm of snow, with the highest accumulations around Kootenay Pass. This snow has been blown around by southwest wind and sits above hard layers of wind pressed snow and crusts. There are reports of several layers 30-60 cm below the surface that could develop into avalanche problems in the future. These layers could be composed of facet/crust layers or surface hoar depending on aspect and elevation. While these layers have produced some notable results in snowpack tests, there are no reports of avalanches on these layers yet. 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 near ridgetops that have been loaded by blowing snow.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Dec 7th, 2019 5:00PM

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