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Archived

Avalanche Forecast

Jan 10th, 2012–Jan 11th, 2012
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
1: Low
The avalanche danger rating at treeline will be low
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
1: Low
The avalanche danger rating at treeline will be low
Below Treeline
1: Low
The avalanche danger rating below treeline will be low

Regions: Sea To Sky.

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.

Avalanche Problems

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

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