Avalanche Forecast

Issued: Dec 21st, 2012 9:52AM

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

Saturday: Mostly clear skies / Moderate southeast winds / Temperature inversion with ridgetop temperature of -14.0Sunday: Mostly clear skies with trace amounts of new snow / Moderate southeast winds / Temperature inversion with ridgetop temperature of -14.0Monday: Trace amounts of new snow / Light southeast winds / Ridgetop temperature of -17.0

Avalanche Summary

No recent avalanches have been reported.

Snowpack Summary

Light amounts of new snow overlie older storm and windslabs which have likely settled and gained strength. 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. Of concern is a November facet/crust layer which can be found near the base of the snowpack. This layer, which seems widespread, is possibly 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.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Deep Persistent Slabs

A deeply buried facet/crust weakness exists. This layer could be triggered by large loads, such as a cornice collapse or a rider digging deeply with a spinning track in a shallow spot on a steep slope.

Conditions have most likely improved, but be mindful that deep instabilities are still present.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Valid until: Dec 22nd, 2012 2:00PM