Avalanche Forecast

Issued: Jan 10th, 2012 9:31AM

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

Avalanche Canada jfloyer, Avalanche Canada

Summary

Confidence

Good - -1

Weather Forecast

A ridge of high pressure will keep the region dry and sunny for Wednesday, Thursday and Friday. Winds will be light and variable throughout. There is a pulse of warm air encroaching into the region from the coast. This may cause an above-freezing level layer to form from 1800-2200m on Wednesday and it's possible this will persist into Thursday and Friday.

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. The event on Tuesday is a good reminder that the storm slab instability can stay reactive for some time after the end of the storm. 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. 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 - Likely

Expected Size

1 - 4

Persistent Slabs

An icon showing Persistent Slabs
Primarily a concern in the northern part of the region. Difficult to trigger, but possible from an area with a shallow, rocky snowpack.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 6

Valid until: Jan 11th, 2012 8:00AM

Login