Avalanche Forecast

Issued: Feb 7th, 2012 9:18AM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is low. Known problems include Wind Slabs, Cornices and Deep Persistent Slabs.

Avalanche Canada ccampbell, Avalanche Canada

Summary

Confidence

Good - -1

Weather Forecast

Mainly cloudy with a chance of flurries for the forecast period. Freezing levels are expected to remain in valley bottoms. Winds could get quite gusty, but generally moderate from the southwest.

Avalanche Summary

Over the weekend widespread natural deep slab avalanche activity to Size 3 was reported. The avalanches occurred in response to a warming pattern that affected much of BC. Avalanche activity has decreased dramatically with the current cooling trend.

Snowpack Summary

The current snow surface is well on its way in becoming a dangerous weak layer once a sufficiently cohesive slab develops. Surface hoar is continuing to develop on sheltered slopes at all elevations combined with near-surface facets at lower elevations and surface crusts on sun-exposed slopes. At the base of the snowpack basal facets and depth hoar seem fairly widespread in the region. Basal facets recently became active again with warm temperatures, and remain a concern with heavy triggers, such as airborne sled impacts and cornice falls, on steep unsupported alpine slopes. In Elk Valley North and the Crowsnest, the average snowpack depth at treeline is 150 cms. In Elk Valley S and the Flathead the snowpack depth is closer to 2 m.

Problems

Wind Slabs

An icon showing Wind Slabs
Fresh wind slabs are expected to develop below ridge crests and behind terrain breaks in lee and cross-loaded terrain.

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Cornices

An icon showing Cornices
Cornices are large, unsupported and may be a trigger for a large avalanche on the slope below.

Aspects: North, North East, East.

Elevations: Alpine.

Likelihood

Possible

Expected Size

3 - 6

Deep Persistent Slabs

An icon showing Deep Persistent Slabs
Deep and destructive persistent slabs have become less likely, but may be triggered with a large trigger (cornice fall, trenching sled); especially in unsupported, rocky terrain.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 6

Valid until: Feb 8th, 2012 3:00AM

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