Avalanche Forecast

Issued: Mar 23rd, 2012 4:00PM

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

pmarshall, Avalanche Canada

Northwest Coastal.

Strong solar radiation and mild temperatures this weekend could result in elevated avalanche danger during the day, particularly on sun-exposed slopes.

Summary

Confidence

Good

Weather Forecast

A ridge of high pressure should maintain mostly dry and sunny conditions throughout the forecast period. There is a chance of more cloud and light precipitation on Monday if a forecast frontal system pushes a little further north. The freezing level is around 900m on Saturday and 1200-1500m on Sunday and Monday. Winds are generally light from the south.

Avalanche Summary

On Thursday there were reports of a couple small (Size 1) accidentally triggered slab avalanches in steep, exposed, lee terrain features. There were also loose-wet avalanches up to Size 1.5 from steep solar aspects.

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 - 3

Loose Wet

Loose wet avalanches are likely on steep sun exposed slopes in the afternoon.

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

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

1 - 3

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

Valid until: Mar 24th, 2012 9:00AM