Avalanche Forecast

Issued: Dec 8th, 2012 9:21AM

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.

Avalanche Canada swerner, Avalanche Canada

Summary

Confidence

Poor - Due to limited field observations for the entire period

Weather Forecast

Sunday: A short lived period of high pressure exists into midday Sunday. In the afternoon a weak upper trough approaches bringing cloudy skies, cooler temperatures, and moderate-strong West winds. Snow amounts 5-10 cm, alpine temps near -9, freezing levels at valley bottom.Monday: Trace of new snow, ridgetop winds NW 40-60 km/hr, alpine temps near -9, freezing levels valley bottom.Tuesday: Moderate snow fall amounts, ridgetop winds SW 30 km/hr, alpine temps near -8, freezing levels 1100 m in the afternoon falling to valley bottom overnight.

Avalanche Summary

No recent avalanche observations.

Snowpack Summary

Recent storm accumulations have been variable throughout the region, however some ares saw significant snowfall earlier in the week. Recent accumulations may sit over a rain crust that extends up to 2000 m, the new snow may have a poor bond to this crust. Widespread wind slabs exist at higher elevations, although I suspect that in recent days they may have gained some strength. 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 an 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

An icon showing Wind Slabs
New snow and winds have created new wind slabs. Watch for triggering in gullies, below ridgecrests and behind terrain features
Whumpfing, shooting cracks and recent avalanches are all strong indicators of an unstable snowpack.>Be alert to conditions that change with elevation.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 4

Deep Persistent Slabs

An icon showing 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 large, deep avalanches due to the presence of a buried crust.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 6

Valid until: Dec 9th, 2012 2:00PM

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