Avalanche Forecast

Issued: Feb 1st, 2012 9:46AM

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

Avalanche Canada triley, Avalanche Canada

Summary

Confidence

Fair - Freezing levels are uncertain on Friday

Weather Forecast

The freezing level is expected to drop down to about 600 metres by Thursday morning. Thin high clouds combined with light southerly winds and warm temperatures are forecast for Thursday. Warm temperatures with freezing levels up to about 1200 metres are expected to continue overnight into Friday. Friday is expected to be warm with light winds and high clouds. A weak pulse of precipitation may move into the region on Friday afternoon bringing trace amounts of snow to higher elevations. The ridge of high pressure is expected to re-build again on Saturday, bringing cooler temperatures. Mostly clear skies may produce intense solar radiation during the day on Saturday.

Avalanche Summary

Soft slab avalanches up to size 1.0, some skier controlled and some skier accidental on steep NE facing alpine terrain. One natural cornice reported as size 2.5 on a NE aspect in the alpine.

Snowpack Summary

The new snow has developed soft slabs in the alpine and at treeline. Storm slabs that developed on the weekend have gained significant strength, as have the heavy storm snow accumulations from last week. Cornices should also be on your radar as strong southwest winds and steady snowfall have contributed to impressive development. About a metre down there are a variety of older snow surfaces that formed throughout January. These surfaces include facets, old wind slabs, and crusts. These interfaces have also gained considerable strength, but triggering may be possible with a heavy load in isolated terrain. Previous concerns about deeper persistent weak layers appear to have diminished. Snowpack depths at treeline are in the region of 260 cm.

Problems

Wind Slabs

An icon showing Wind Slabs
Wind slabs are expected to settle and bond due to warm temperatures on Thursday. If the warm temperatures continue through the night on Thursday, the warming trend may be too rapid and cause instability on Friday.

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 4

Storm Slabs

An icon showing Storm Slabs
Storm slabs are expected to gain strength and continue to bond to the old surface. If the warm temperatures continue through the night on Thursday, the warming trend may be too rapid and cause instability on Friday.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

1 - 5

Cornices

An icon showing Cornices
Strong winds and new snow have added mass to sensitive cornices. They may be destructive by themselves, and may also be a trigger for the slope below.

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

Elevations: Alpine.

Likelihood

Likely

Expected Size

1 - 6

Valid until: Feb 2nd, 2012 3:00AM