Avalanche Forecast

Issued: Jan 20th, 2012 9:18AM

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

triley, Avalanche Canada

Northwest Coastal.

Summary

Confidence

Fair - Forecast snowfall amounts are uncertain on Saturday

Weather Forecast

Strong northeast outflow winds are expected to continue until at least Saturday afternoon. The temperature is expected to rise to about -12.0 in the alpine by Saturday morning. Blowing snow overnight should accumulate to about 15 cm by Saturday morning. Sometime Saturday afternoon or evening, the winds should shift to the southwest and become strong and gusty. The snowfall is expected to increase overnight, bringing an additional 20 cm by Sunday morning. Precipitation should decrease during the day Sunday, followed by another pulse of warmer wet weather on Monday.

Avalanche Summary

Some natural and cornice triggered avalanches up to size 2.5 have been reported from slopes that were loaded by the recent strong NE winds.

Snowpack Summary

The deep snowpack is considered to be well settled with no persistent layers of concern. Some areas have about 20 cm of dry cold snow above the old storm snow that ended about January 8th. Windslabs that have developed due to strong NE outflow winds have not bonded to this layer. Some areas have developed surface hoar or surface facetting on sheltered slopes in the alpine and at treeline.

Problems

Wind Slabs

Old stiff windslabs have developed on South through West aspects due to strong northeast winds in the alpine and at treeline. New soft windslabs are expected to develop with the approaching strong southerly winds and new snow.

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 5

Storm Slabs

Forecast strong southerly winds combined with moderate precipitation may develop a storm slab. If temperatures remain cool the new snow may continue to be loose and dry causing widespread sluffing.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 4

Valid until: Jan 21st, 2012 8:00AM