Avalanche Forecast

Issued: Mar 22nd, 2012 11:35AM

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

pgoddard, Avalanche Canada

Cariboos.

Avalanche danger could spike to HIGH on any slopes which are getting baked by sun. Avoid traveling on, or underneath such areas.

Summary

Confidence

Fair - Timing or intensity of solar radiation is uncertain

Weather Forecast

Friday-Sunday: Sunny. Light southerly winds. Freezing level rising to around 1500m in the afternoon and falling to valley floor at night.

Avalanche Summary

Over the last couple of days, little activity has been reported, except a size 3 natural avalanche on a north-east aspect and a size 1 storm slab, triggered by a skier. On Monday, natural avalanches up to size 3.5 failed on southerly aspects down about 100-150cm on the mid-February persistent weak layer. Avalanches releasing on this layer are becoming less frequent. Solar warming is of particular concern over the next few days, as it could destabilize storm slabs 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

20-30 cm recent storm snow overlies various surfaces including settled snow, wind slabs and crusts. New wind slabs have formed in the alpine and at treeline. Solar warming last weekend left a melt-freeze crust up to about 2400 m on solar aspects and up to about 1500 m on all aspects. Cornices have grown large and unstable. A consolidated storm 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

Wind Slabs

Wind slabs in the alpine and at treeline may take a few days to settle and bond. Cornices are very large and also threaten slopes below.

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 4

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

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 may spark renewed activity.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

3 - 8

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