Avalanche Forecast

Issued: Jan 15th, 2012 9:50AM

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

pgoddard, Avalanche Canada

South Coast.

If winds pick up in your area, expect the danger to be considerable in the alpine. Wind slabs may build very quickly. However, forecast wind values are uncertain.

Summary

Confidence

Fair - Forecast snowfall amounts are uncertain

Weather Forecast

Monday: Cold with some flurries. Freezing level near surface.Tuesday: Light snow. Westerly winds. Cold.Wednesday: Moderate-heavy snow (poor confidence in Wednesday's snowfall amounts at this stage - stay posted).

Avalanche Summary

Skiers triggered slabs up to size 2 in the Coquihalla region on Saturday (incident reports here: https://avalanche.ca/cac/library/incident-report-database/view). In other parts of the region, storm snow was failing naturally and reacting easily to ski cuts. These results involved the storm snow and did not dig down to any deeper weaknesses.

Snowpack Summary

20-40cm of dry new snow has landed on a hard supportive crust in the Coquihalla area and dry facets in the Duffey Lake area. Snowpack tests showed a poor bond to the old surfaces on Saturday and improved results on Sunday. West to south-westerly winds created soft slabs, which seem to have gained strength. If winds increase again, new wind slabs are likely to form quickly as there is plenty of dry new snow available to be transported.Deeper in the snowpack, two persistent weak layers remain a concern only in thin snowpack areas (perhaps wind-scoured zones or relatively dry eastern ranges) and particularly in steep rocky terrain or sheltered, low-snowpack terrain. The two layers are surface hoar and/or facets associated with a crust from mid-December and sugary facets at the base of the snowpack.

Problems

Wind Slabs

New wind slabs may form behind ridges and terrain breaks. Older wind slabs appear to be gaining strength, but should still be treated with caution.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 5

Loose Dry

Loose, dry new snow can sluff easily in steep ground. It could trip you up or push you into a terrain trap.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Valid until: Jan 16th, 2012 8:00AM