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Avalanche Forecast

Dec 8th, 2012–Dec 9th, 2012
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate

Regions: South Rockies.

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.

Avalanche Problems

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

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