Avalanche Forecast

Issued: Dec 18th, 2017 4:30PM

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

Avalanche Canada mgrist, Avalanche Canada

Fresh storm slabs will be driving the avalanche danger on Tuesday. Be extra vigilant on down wind (lee) features below ridge crests.

Summary

Confidence

Moderate - Intensity of incoming weather systems is uncertain on Tuesday

Weather Forecast

Active weather returns on Tuesday with moderate amounts of snow and cool temperatures. TUESDAY: Snow. 5cm overnight with 10-15cm accumulation throughout the day. Ridge wind moderate from the east. Temperature near -5. Freezing level 500 m.WEDNESDAY: Sunny with cloudy periods. Ridge wind moderate northerly. Freezing level at the surface.THURSDAY: Cloudy with isolated flurries. Ridge wind moderate from the north west. Temperature near -3. Freezing level 400 m.

Avalanche Summary

On Monday, ski cutting and explosives control work produced several Size 1 to 1.5 storm slabs on steep northerly features at higher elevations. On Sunday, natural and cornice triggered storm slabs to Size 1 were reported on northerly aspects in the alpine.

Snowpack Summary

10-30 cm of new snow covers the melt-freeze crust that formed on all aspects and elevations in early December. On high north aspects this crust is thin with dry, sugary snow crystals (facets) below. Moderate winds from the south (west) have redistributed snow, creating isolated soft slabs on downwind slopes and behind ridges (north through east aspects). Beneath the surface, the upper snowpack is well settled and overlies a thin layer of facets on the late-November rain crust, which is now down approximately 60 cm at tree line elevations. The lower snowpack is well settled and consists of several crusts that formed in the early season.

Problems

Storm Slabs

An icon showing Storm Slabs
Winds during Tuesday's storm will be from the (north) east - which is not the usual pattern we see. Watch out for storm slabs on west through northerly aspects.
Be careful with wind loaded pockets, especially near ridge crests and roll-overs.Avoid steep convex slopes.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Valid until: Dec 19th, 2017 2:00PM