Avalanche Forecast

Issued: Dec 2nd, 2012 3:00PM

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

Alberta Parks mike.koppang, Alberta Parks

Lots of snow is currently available for transport at treeline elevations and above.  Pay close attention to winds as skier triggerable slabs will be quick to develop as winds increase.  Good skiing being found in sheltered areas.

Summary

Confidence

Fair - Forecast snowfall amounts are uncertain on Tuesday

Weather Forecast

Light precip is forecast to continue under the influence of a light to moderate SW flow.  Convective flurries may give locally moderate precip in some areas so pay close attention.  Temperatures are expected to remain seasonal.  Pay close attention to winds as our forecast models are in conflict with one model calling for light winds and another calling for strong winds.  Lots of snow is currently available for transport so if winds do increase, stability will be quick to decrease.

Avalanche Summary

A few loose dry avalanches for steeper unskiable terrain up to size 2.  Skies were obscured most of the day and forecasters had limited opportunities to get a good look up and into Alpine areas.

Snowpack Summary

Up to 35cm of recent snowfall over the past 48hrs.  This snow has fallen with little to no wind affect except for at higher elevations (above 2500m).  Pockets of storm slabs  up to 30cm thick are being encountered along ridgelines and in cross-loaded features but these slabs do not appear to extend far downslope.  Easy sheers persist within the storm snow down 30-40cm.  The Nov crust is now down 100cm and hard sheers persist in a facet layer below the crust.  Lots of snow is currently available for transport and storm slabs will be quick to build with the influx of moderate winds.

Problems

Storm Slabs

An icon showing Storm Slabs
Storm slab formation is ongoing. Up to 35cm of recent snow has fallen and winds are moderate at higher elevations from the SW. Stability tests today indicate that the storm slabs are getting easier to trigger, particularly in the Alpine.
Avoid lee and cross-loaded terrain near ridge crests.>Avoid North-East slopes at or above treeline.>Avoid unsupported slopes.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 5

Loose Dry

An icon showing Loose Dry
Be cautious of sluffing in steep terrain.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Very Likely

Expected Size

1 - 2

Persistent Slabs

An icon showing Persistent Slabs
The Nov rain crust persists about 30cm off the ground throughout the forecast area and is reactive to stability tests in the hard range. Avalanches in the upper snowpack may step down to this weakness.
Be aware of the potential for full depth avalanches due to deeply buried weak layers.>Be aware of thin areas that may propagate to deeper instabilites.>

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 6

Valid until: Dec 3rd, 2012 2:00PM

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