Avalanche Forecast

Issued: Dec 2nd, 2011 9:20AM

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

Avalanche Canada jlammers, Avalanche Canada

Summary

Confidence

Poor - Due to limited field observations

Weather Forecast

A mostly dry northwesterly flow will make its way into the region for saturday, sunday and monday. Winds should remain moderate and northwesterly at ridgetop for the period with freezing levels remaining at or around surface.

Avalanche Summary

Widespread size 2 natural activity reported from the region on wednesday. Any observations from the field are welcome. Please send to forecaster@avalanche.ca

Snowpack Summary

Expect to find around 200cm of snow near treeline. In the alpine there's either more or less depending on local wind patterns. I suspect last weekend's storm snow is settling into place and gaining strength. The snow and wind that occurred over the last few days will have created pockets of touchy windslab that will be lingering on lee and cross-loaded features at treeline and in the alpine; forecast northerly winds may reverse & complicate the pattern with E through S facing slopes building new ones. A rain crust that developed on November 27th is about 20-35 cms below the surface (elevation dependant). It`s about 2 cms thick at 1700m and is reportedly 'bullet-proof' closer to valley bottom. No activity has been reported yet on this crust, but it's something to keep on your radar. Closer to the ground is the early November surface hoar; somewhere around 50 cm above ground or 150 cm below the surface. It may be difficult to trigger this layer but has a sudden planar characteristic. I also suspect a lingering rain crust down there. It's still November (just barely), so we only have a teenage snowpack at best: variable, unpredicable, maybe moody. I suggest giving the snowpack a few days to reveal its secrets.

Problems

Wind Slabs

An icon showing Wind Slabs
Expect touchy windslabs in lee or cross-loaded terrain. The nature of this problem may become more complicated with forecast northerly winds.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Persistent Slabs

An icon showing Persistent Slabs
Probability of triggering has decreased. Where it still exists, this layer may be capable of producing highly destructive, full depth avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 6

Valid until: Dec 3rd, 2011 8:00AM

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