Avalanche Forecast

Issued: Dec 4th, 2011 8:52AM

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

Avalanche Canada triley, Avalanche Canada

Summary

Confidence

Fair - Freezing levels are uncertain

Weather Forecast

The ridge of high pressure is forecast to continue to bring clear skies to the region on Sunday night and Monday. There is a temperature inversion forecast to move into the area from the Northwest. This means that it may be warmer in the Alpine than it is in the valley. This condition should be fairly short lived on Monday, and then replaced with below freezing temperatures down to the valleys by Tuesday morning. Strong South-westerly winds are forecast for Tuesday morning as a fast moving cold front move through the region. The ridge of high pressure should re-build on Wednesday, and there may be another period of above freezing temperatures in the alpine.

Avalanche Summary

No new avalanche activity has been reported. If you have any avalanche observations to report, please email us at: forecaster@avalanche.ca.

Snowpack Summary

A rain crust is now present below 1800m which may be a layer to watch as it get buried. The main concern in the upper part of the snowpack is wind slabs. Earlier in the week treeline and alpine winds were strong from the south-southwest. Winds have switched and are now blowing from the north-west. With Tuesday's new snow to transport, you can expect to find stiff wind slabs on many aspects, cross loading, and deeper stiffer pockets lee of terrain features. My guess is that the good riding with quality pow turns will be in sheltered locations that were unexposed to wind. Generally there is about 150-200cm in the alpine. Treeline depths are between 50 -150cms. Recent snow pack observations are indicating the late October rain crust is present in the alpine elevations and down approximately 120cm. This crust is said to be up to 5mm in thickness with predominate faceting below it. For the moment the crust seems to be bridging over the facets below, with a well settled midpack above.

Problems

Wind Slabs

An icon showing Wind Slabs
Due to shifting winds, wind slabs may be found on all aspects. If a weakness exists lower in the snowpack, a wind slab release may step down deeper producing larger avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 4

Valid until: Dec 5th, 2011 8:00AM