Avalanche Forecast

Issued: Apr 15th, 2013 11:22AM

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

pgoddard, Avalanche Canada

Cariboos.

Summary

Confidence

Fair - Due to variable snowpack conditions

Weather Forecast

Tuesday: No snow. Light winds. Freezing level near 1300 m. Wednesday: Light snow. Moderate SW winds. Freezing level near 1500 m. Thursday: Moderate snow. Light to moderate SW winds. Freezing level near 1600 m.

Avalanche Summary

Several loose avalanches to size 2 were observed on Sunday. A cornice fall also triggered a size 2 avalanche in steep terrain.

Snowpack Summary

Up to 40 cm recent storm snow has been shifted by variable winds into wind slabs at treeline and above. Below treeline, warm daytime temperatures have been softening the snow surface.Some professionals are expressing concern for a surface hoar interface buried within the upper metre or so of the snowpack, mainly on high-elevation northerly aspects. It may be slowly gaining some strength, but these slopes should still be treated with suspicion. On other slopes, recent storm snow overlies a crust. This crust interface has recently become reactive in regions further south. Cornices in the region are very large and potentially destructive.

Problems

Wind Slabs

Recent snowfall has been redistributed by changing winds. Wind slabs exist on a variety of aspects at treeline and above. Wind has also formed very large and potentially unstable cornices.

Avoid freshly wind loaded features.>Use ridges or ribs to avoid pockets of wind loaded snow.>Do not travel on slopes that are exposed to cornices overhead.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 4

Persistent Slabs

A weak interface is buried about a metre down. A surface avalanche stepping down, cornice fall, or the weight of a person from a thin-spot trigger point could trigger it.

Choose well supported terrain without convexities.>Be aware of the potential for large, deep avalanches due to the presence of buried weak layers.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

2 - 6

Valid until: Apr 16th, 2013 2:00PM