Avalanche Forecast

Issued: Mar 24th, 2012 10:29AM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is considerable. Known problems include Deep Persistent Slabs, Cornices and Loose Wet.

jlammers, Avalanche Canada

Cariboos.

Strong solar radiation is expected throughout the weekend. When solar radiation is strongest, the avalanche danger may exceed posted levels.

Summary

Confidence

Fair - Timing or intensity of solar radiation is uncertain

Weather Forecast

Sunday: Clear skies - very light southwest winds - freezing level at 1700m Monday: Increased cloud with the possibility of very light snowfall - light southwest winds - freezing level at 1500m Tuesday: Trace amounts of snowfall with possible clearing in the afternoon - moderate southwest winds - freezing level at 1500m

Avalanche Summary

A size 2.5 natural slab avalanche was observed on a north aspect at 2300m. Details of the weak layer are uncertain. A size 2 natural avalanche was also observed having reacted on a crust on a southeast facing slope at 2000m. Solar warming is of particular concern this weekend, as it could destabilize surface snow and cornices, potentially initiating deep failures on the mid-February layer. Be particularly wary of sunny aspects during the heat of the day.

Snowpack Summary

Recently formed wind slabs exist in the alpine and at treeline. Solar radiation has led to moist surfaces on sun exposed slopes with good crust recovery developing at night. Cornices have grown large and unstable. A consolidated deep slab overlies weak surfaces that formed in early February. Now 1-2 m below the surface, these weaknesses include surface hoar, facets or crusts. Operators continue to express concern about the potential for deep releases on these interfaces.

Problems

Deep Persistent Slabs

A weak interface down 1-2m remains concerning. While avalanches on this layer have become less frequent, those that do release are very large and destructive. Solar warming this weekend may spark renewed activity.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

3 - 8

Cornices

Large cornices exist and are becoming more likely to fail under intense solar radiation. A cornice fall could trigger a very large avalanche on the slope below. Wind slabs also exist at higher elevations.

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

Elevations: Alpine.

Likelihood

Likely

Expected Size

1 - 5

Loose Wet

Solar warming is likely to cause loose wet avalanches, especially on steep, rocky, south-facing terrain.

Aspects: North, North East, East.

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

1 - 5

Valid until: Mar 25th, 2012 9:00AM