Avalanche Forecast

Issued: Jan 11th, 2012 8:21AM

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

Avalanche Canada jfloyer, Avalanche Canada

Summary

Confidence

Fair - Timing of incoming weather is uncertain on Saturday

Weather Forecast

Another clear and sunny day for Thursday, although high cloud may begin to develop in the afternoon. Mild temperatures are expected in the alpine, due to an above freezing level layer from approximately 1200 to 2200m. Light westerly winds. On Friday, clouds will build during the day but it should remain dry. Freezing levels will be around 2000 m. On Saturday, freezing levels will fall to about 500 m and a frontal system will bring moderate precipitation, which should fall as snow, although there is the possibility for a little bit of rain at the beginning of the storm. Gusty winds will be a feature of the next storm.

Avalanche Summary

There were reports of two skier-triggered avalanches near Whistler that went on the recent storm snow interface down around 60 cm, one from Monday and one from Tuesday. Both were size 2 and released on a NE aspect around 2000 m. There have been no recent reports of activity stepping down to any of the lower weak layers in the snowpack.

Snowpack Summary

At treeline, snowpack depths are around 260cm.The upper snowpack comprises a series of storm snow layers, which have generally bonded well to each other and are now gaining strength. Rain to approximately 2000 m from the last storm that has now refrozen has left us with a crust buried by a skiff of snow. In the alpine, above the elevation where rain fell, fresh new wind slabs have developed in response to very strong winds. Expect winds to shift from southwesterly to northerly, potentially creating some localized reverse loading. Cornices Concern for lower snowpack layers remains only in shallow snowpack areas. Facets associated with a crust from mid-December and/or sugary facets at the base of the snowpack could be a concern in areas you know to be unusually shallow, or where you can see rocks poking up out of the snow.

Problems

Wind Slabs

An icon showing Wind Slabs
Watch for wind slabs in the immediate lee of ridge crests.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Cornices

An icon showing Cornices
Warm alpine temperatures will promote well developed cornices to collapse.

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

Elevations: Alpine.

Likelihood

Likely

Expected Size

1 - 4

Valid until: Jan 12th, 2012 8:00AM