Avalanche Forecast

Issued: Dec 22nd, 2012 9:21AM

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

jlammers, Avalanche Canada

Northwest Inland.

Summary

Confidence

Poor - Due to limited field observations

Weather Forecast

Mainly clear skies are expected for the forecast period. Expect temperature inversions with ridgetop temperatures of about -17.0. Winds should be mostly light and southeasterly with strong northeasterly outflows.

Avalanche Summary

No recent avalanches have been reported.

Snowpack Summary

Light amounts of recent snow overlie older storm and windslabs. It is suspected that the recent light accumulations have been redistributed into wind slabs in some areas.Spotty surface hoar was buried in the upper snowpack in sheltered treeline areas, although little is known about its reactivity. A facet/crust layer which formed in early November can be found near the base of the snowpack. This layer, which seems widespread, is probably gaining some strength. Having said that, it may be triggered from thin-spot trigger points, or with a heavy load and has the potential for large, destructive avalanches. In general the snowpack depths, and therefore strength, is highly variable due to windy conditions this season.

Problems

Wind Slabs

Wind data in the region has been very sparse. If local wind values have been moderate or higher, wind slabs may exist in gullies and in the lee of terrain breaks.

Be cautious as you transition into wind affected terrain.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Deep Persistent Slabs

A deeply buried facet/crust weakness exists. This layer could be triggered by large loads such as a cornice collapse.

Avoid convexities or areas with a thin or variable snowpack.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Valid until: Dec 23rd, 2012 2:00PM