Avalanche Forecast

Issued: Dec 29th, 2012 9:33AM

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

Avalanche Canada slemieux, Avalanche Canada

Summary

Confidence

Fair - Due to limited field observations

Weather Forecast

Saturday night and Sunday: An upper ridge remains over the coast bringing dry conditions and light W winds until a front reaches the coast in the evening Sunday. Monday: Only traces of precipitations associated with the weak front are expected to reach inland and winds should be felt moderate to strong from the Southwest. Freezing levels are expected to remain at the surface but temperatures to warm up slightly with the arrival of the front. Tuesday: Temperatures around -4 C, no precipitation, light SE winds.

Avalanche Summary

No recent avalanches have been reported.

Snowpack Summary

A few cm fell since yesterday with relatively light winds from the NW.  As a general overview, a shallow snowpack (about 1m deep) exists, with facets that have continued to develop with this week's cool arctic air. Strong winds have scoured some SE aspects in the alpine to ground. Wind slabs exist in many wind-exposed areas, however their distribution is quite variable and some areas have no wind-effect at all. Below treeline, very loose cold snow is sluffing easily from steep terrain and early season hazards like exposed stumps are still to watch for. Professionals are still mindful of a facet/crust layer near the base of the snowpack. Although triggering it has become unlikely, it may be possible from a thin-spot trigger point or with a very heavy load (e.g. cornice fall).

Problems

Wind Slabs

An icon showing Wind Slabs
Watch for wind slabs behind ridges and terrain breaks. These could be triggered by the weight of a person or snowmobile.
Be cautious as you transition into wind affected terrain.>Be aware of the potential for wide propagations due to the presence of hard windslabs.>

Aspects: North, North East, East, South East, South.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 4

Deep Persistent Slabs

An icon showing Deep Persistent Slabs
A deeply buried facet/crust weakness exists near the base of the snowpack. This layer could be triggered by large loads such as a cornice collapse or from a thin-spot trigger point.
Be aware of thin areas that may propagate to deeper instabilites.>Choose the deepest and strongest snowpack areas on your run.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Valid until: Dec 30th, 2012 2:00PM

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