Avalanche Forecast

Issued: Dec 22nd, 2011 9:02AM

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 on the weekend.

Summary

Confidence

Fair - Intensity of incoming weather is uncertain on Saturday

Weather Forecast

Friday: Light snowfall with 2-5cm of accumulation, moderate southwesterly winds, and freezing levels around 1300m. Saturday: 5-15cm of new snow expected with moderate to strong westerly winds and freezing levels rising as high as 1600m late in the day. Sunday: Trace amounts of new snow expected with freezing levels again reaching 1600m and moderate westerly winds.

Avalanche Summary

Recent reports include isolated human triggered Size 1 thin soft wind slab avalanches running on large surface hoar, on south through east facing treeline slopes.

Snowpack Summary

Surface hoar is is growing on the snow surface again and some areas have three different surface hoar layers buried in the top 15cm, but the deepest layer is largest and most widespread across the region. 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 attention 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 23rd, 2011 8:00AM

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