Avalanche Forecast

Issued: Dec 21st, 2011 8:37AM

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

Summary

Confidence

Fair - Timing, track, or intensity of incoming weather is uncertain on Saturday

Weather Forecast

Thursday: Mostly clear with freezing levels rising as high as 1300m and moderate to strong westerly winds. Friday: A mix of sun and cloud, but dry, with freezing as high as 1500m and moderate to strong westerly winds. Saturday: Light to moderate snowfall expected primarily on the western side of the ranges. Freezing levels expected to remain around 1500m, and strong southwesterly winds.

Avalanche Summary

Recent avalanche activity has been limited to isolated minor sluffing on steep shady slopes.

Snowpack Summary

Light amounts of new snow has covered new surface hoar overlying 10-15 cm low density snow sitting on another weak layer of large surface hoar and/or facets, with an associated crust on sun-exposed slopes. The uppermost surface hoar may not yet be fully protected from the elements that can destroy it, such as sun, wind, and especially rain, but at this point it seems to be just as widespread but smaller than the deeper layer. A sufficiently cohesive slab for fracture propagation and avalanche release has formed on wind-loaded slopes, but for the most part, the slab is neither deep nor stiff enough for large avalanches. Check out the Forecaster's Blog link below for a discussion on incremental loading of potentially persistent weak layers. The mid and lower snowpack are generally well-settled and strong, but recent reports suggest basal facets create a deep persistent slab problem that deserves caution in shallow snowpack areas on planar rocky slopes.

Problems

Wind Slabs

An icon showing Wind Slabs
Fresh wind slabs are lurking below ridge crests, behind terrain features, and in cross-loaded gullies.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Dec 22nd, 2011 8:00AM