Avalanche Forecast

Issued: Dec 14th, 2011 8:23AM

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

Avalanche Canada ccampbell, Avalanche Canada

Avalanche danger is expected to increase throughout the forecast period.

Summary

Confidence

Fair - Intensity of incoming weather is uncertain on Friday

Weather Forecast

Thursday: Another 2-4cm before the snowfall tapers off in the morning, with 10-15cm total storm snow. Moderate southeasterly winds are expected to shift to clearing in the afternoon. Freezing levels should remain in valley bottoms. Friday: Light to moderate snow with another 5-10cm possible. Moderate southerly winds and freezing levels rising to 1000m. Saturday: Moderate snowfall starting in the afternoon with 5-15cm expected. Moderate to strong southewesterly winds and freezing levels as high as 2000m in the morning but dropping throughout the day.

Avalanche Summary

There have been no new reports of avalanches. Fresh soft wind slabs are expected to form and become an avalanche problem.

Snowpack Summary

Large surface hoar and faceted powder on sheltered shady slopes, and a surface crust on sun-exposed slopes, is now lightly buried in some locations and should continue to get incrementally buried over the forecast period. Assuming the structure of this current snow surface is preserved long enough for a sufficiently thick and cohesive slab to bury it, then a highly unstable situation should develop. Particularly where surface hoar and/or faceted crystals are associated with a weak crust. Generally speaking the longer surface snow is exposed to the elements before it gets burred, the more likely it is to become a serious problem. The mid and lower snowpack are generally well settled and strong, but faceted. Basal facets and depth hoar necessitate caution on wind-exposed slopes with highly variable snowpack depths, where this deep persistent weakness could be triggered from a shallow spot. Check out the Forecaster's Blog link below for more general snowpack discussion and good advice.

Problems

Wind Slabs

An icon showing Wind Slabs
Fresh soft wind slabs are expected to develop below ridge crests and behind terrain features throughout the forecast period.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Dec 15th, 2011 8:00AM

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