Avalanche Forecast

Issued: Jan 19th, 2012 9:55AM

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

Avalanche Canada triley, Avalanche Canada

Summary

Confidence

Fair - Forecast snowfall amounts are uncertain on Saturday

Weather Forecast

The cold arctic air should begin to be pushed out of the region starting this evening. Strong northeast outflow winds may continue into the evening, and then be replaced with moderate to strong southerly winds by Friday afternoon. Coastal areas may receive 5-10 cm by Friday morning, and a further 10-20 cm during the day on Friday. Inland areas are expected to get about half as much snow during this period. Freezing levels are expected to remain near the valley bottoms in the Smithers area, and may rise to about 700 metres briefly on Friday afternoon near Terrace. Temperatures are expected to rise to about -4.0 at treeline on Friday and then drop slightly to about -7.0 at treeline on Saturday. Strong south-southwest winds on Saturday should continue on Sunday. A series of Pacific frontal systems will continue to bring precipitation over the next few days.

Avalanche Summary

Some natural and cornice triggered avalanches up to size 2.0 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

An icon showing 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: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 5

Storm Slabs

An icon showing 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 20th, 2012 8:00AM