Avalanche Forecast

Issued: Dec 7th, 2012 9:29AM

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

jlammers, Avalanche Canada

South Rockies.

Summary

Confidence

Poor - Due to limited field observations

Weather Forecast

Overnight and Saturday: Light to locally moderate snowfall on Friday night with clearing on Saturday / moderate northwest winds becoming light and northwest with clearing / Freezing level at surfaceSunday: Light snowfall / moderate northwest winds with extreme gusts / Freezing level at surfaceMonday: Light snowfall / moderate southwest winds / Freezing level at surface

Avalanche Summary

No recent avalanche observations.

Snowpack Summary

Recent storm accumulations have been highly variable throughout the region; however, some ares saw significant snowfall earlier in the week. In general, winds have been moderate to strong creating widespread windslabs at higher elevations, although I suspect that in recent days they may have gained some strength. In some areas the most recent accumulations may sit over a rain crust that extends up to 2000m. There have been reports of buried surface hoar up to a metre down. This layer, which was buried at the end of November, seems most prevalent on the west side of the region. Little is known about its current reactivity.At the base of the snowpack you may find the early November crust which is associated with a layer of facets either directly above or below. Recent tests have shown sudden results at this interface.In general, snowpack data is sparse in this region and significant variations likely exist from one drainage to another. Digging down and making your own observations will be critical to safe slope selection. Any observations from the field are welcome at forecaster@avalanche.ca.

Problems

Wind Slabs

Significant snowfall and winds from earlier in the week have created new wind slabs. Watch for triggering in gullies, below ridgecrests and behind terrain features

Be cautious as you transition into wind affected terrain.>Be alert to conditions that change with elevation.>Avoid travelling in areas that have been reverse loaded by winds.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 4

Deep Persistent Slabs

We have not heard of any new releases on this early season rain crust; however, an avalanche at this interface could be surprisingly large and destructive.

Be aware of the potential for full depth avalanches due to deeply buried weak layers.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 5

Valid until: Dec 8th, 2012 2:00PM