Avalanche Forecast

Issued: Apr 16th, 2013 10:32AM

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 - Timing, track, or intensity of incoming weather is uncertain on Thursday

Weather Forecast

Wednesday: Light snow. Moderate SW winds. Freezing level near 1500 m. Thursday: Light snow. Light to moderate SW winds. Freezing level near 1800 m. Friday: Moderate snow. Light SW winds. Freezing level near 1800 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. No avalanches were reported on Monday.

Snowpack Summary

Strong NE winds have created wind slabs at treeline and above on lee slopes, and scoured windward aspects. Cornices in the region are very large and potentially destructive. 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.

Problems

Wind Slabs

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

Be cautious as you transition into wind affected terrain.>Travel on ridgetops to avoid wind slabs on slopes below.>Avoid steep slopes below cornices.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

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 thin areas that may propagate to deeper instabilites.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

2 - 6

Valid until: Apr 17th, 2013 2:00PM