Avalanche Forecast

Issued: Dec 4th, 2016 3:46PM

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

Avalanche Canada swerner, Avalanche Canada

Fresh storm slabs that formed over the weekend may be reactive to rider triggers especially on slopes that have seen more wind loading.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain on Monday

Weather Forecast

Unsettled conditions continue overnight into Monday as an upper trough moves from the north bringing flurries tonight. A cool arctic air mass will dominate the region by Tuesday bringing colder, dryer conditions. Monday: Mostly cloudy with flurries. Alpine temperatures near -13 with light winds from the northeast. Tuesday/ Wednesday: Mix of sun and cloud. Alpine temperatures dropping to -20 with light winds from the northeast.

Avalanche Summary

On Saturday, numerous natural storm slab avalanches were reported. These avalanches were up to size 2 and running on north-northeast aspects above 1700 m. Explosive control also triggered several slabs up to size 2. The crowns were 20-40 cm deep and running up to 160 m in length. These slabs were mostly failing on an old storm interface and reports haven't indicated any avalanche actively on the buried November crusts. On Sunday, numerous explosive triggered slab avalanches were reported. These were up to size 2 from all aspects. Rider triggers are likely on Monday.

Snowpack Summary

New storm slabs and wind slabs have formed on open leeward slopes and behind terrain features. The threshold for avalanches has been exceeded at treeline and in the alpine as reports suggest that the snow depth at treeline is typically 110-150 cm but a report from the east side of region shows only 80 cm at treeline. The snowpack is still developing below treeline and has yet to reach threshold. Limited reports suggest the crust from the middle of November is down 50-80 cm and the crust from early November is down 80-110 cm.

Problems

Storm Slabs

An icon showing Storm Slabs
New snow accompanied by strong winds are building fresh and reactive storm slabs at upper elevations.
Avoid freshly wind loaded features.Be alert to conditions that change with elevation. Use a conservative approach to terrain.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Dec 5th, 2016 2:00PM