Avalanche Forecast

Issued: Dec 21st, 2011 8:35AM

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 increasing clouds in the afternoon. Freezing levels as high as 1500m, and moderate southwesterly winds. Friday: up to 15cm of snow with freezing levels around 1000m and strong southwesterly winds. Saturday: Another 20-30cm possible, especially for coastal areas, with freezing levels remaining around 1000m and strong westerly winds.

Avalanche Summary

Recent observations are limited to isolated human-triggered Size 1 fresh wind slabs. One was 20m wide by 20cm deep on a NE facing alpine slope.

Snowpack Summary

Dribs and drabs of new snow with associated winds are keeping wind slabs fresh and poorly bonded to the variable but predominately crusty snow surface from last weekend's warm, wet, and windy weather. Recent compression tests on a wind-loaded treeline slope produced easy to moderate sudden collapse results down 65cm on surface hoar overlying faceted snow. The mid and lower snowpack are generally well settled and strong. Weak facets may be lurking at base of the snowpack in shallow alpine areas, but there have been no recent reports of associated instabilities.

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

Expected Size

1 - 3

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