Avalanche Forecast

Issued: Mar 22nd, 2012 4:00PM

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

pmarshall, Avalanche Canada

Northwest Coastal.

The most significant warming looks like it will occur on Saturday and could result in an increase in avalanche activity.

Summary

Confidence

Fair

Weather Forecast

A ridge of high pressure should maintain mostly sunny and dry conditions for the next several days. The freezing level will drop to valley bottom overnight and rise to 800-1000m during the day. Ridge top winds should be generally light from the south.

Avalanche Summary

Reports from Tuesday and Wednesday include several skier controlled slab avalanches up to Size 1.5 (15-30cm deep), primarily from wind loaded terrain features. There were no reports of recent natural avalanche activity.

Snowpack Summary

Moderate SE winds have created thin wind slabs in lee and cross-loaded terrain. 20-40cm of new snow sits on the previous snow surface which included a sun crust on southerly aspects, surface facets or surface hoar in cool shady areas, and pockets of wind slab in exposed terrain. A variety of potential weak layers exist between 60 and 120cm deep. These include surface hoar or facets. There has been no recent activity on these layers but they could wake up with heavy triggers like a large cornice chunk or a snowmobile digging its track in. Cornices in the region are reported to be very large and potentially unstable.

Problems

Wind Slabs

New wind slabs may be triggered in exposed lee and cross-loaded terrain.

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

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 4

Cornices

Cornices are reported to be very large and potentially unstable at this time. A cornice fall could be destructive by itself, and may also act as a trigger on the slope below.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 6

Loose Wet

Loose wet avalanches are likely on steep sun exposed slopes if the sun is shining.

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

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

1 - 3

Valid until: Mar 23rd, 2012 9:00AM