Avalanche Forecast

Issued: Feb 1st, 2013 3:00PM

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

Alberta Parks mike.koppang, Alberta Parks

Another chinook!  Winds are increasing as well as temps!  Watch for fresh storm and windslabs in open wind affected terrain.  Also, there may be some decreases in stability on steep solar aspects as temperatures warm up so use caution.

Summary

Confidence

Good

Weather Forecast

A chinook is rolling through the region once again.  No new snow is expected and winds are forecast to be strong out of the SW at upper elevations.  Skies are expected to be clear so watch for decreases in stability on solar aspects related to the daytime warming.

Avalanche Summary

Only one small sz 1 slab avalanche was observed on Mt Fister (N or Mt Nestor). on a steep E aspect alpine feature.  The slide was 20m wide and ran 100m.

Snowpack Summary

A few new cm of snow at higher elevations.  Close to 30-35cm of new snow is now overlying the 0123 windslabs/storm snow interface.  Mid day on friday the chinook started rolling in, winds increased and storm slabs begin to further develop in Alpine areas sure to the strong SW flow.  The snowpack is weak and facetted in lower elevations but above 2000m the midpack gains strength and improves.  140cm on average at TL.

Problems

Storm Slabs

An icon showing Storm Slabs
Up to 30cm of snow has fallen at upper elevations over the past week.  This snow has formed soft and hard storm slabs up to 30cm thick in Alpine open terrain. 
Be cautious as you transition into wind affected terrain.>Avoid convexities or areas with a thin or variable snowpack.>

Aspects: North, North East, East.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 4

Persistent Slabs

An icon showing Persistent Slabs
Buried windslabs should be expected throughout the region.  These slabs have been buried by the recent snow making them tougher to locate.  Be aware of thin areas surrounding these slabs where the snowpack is weaker.
Be aware of the potential for wide propagations due to the presence of hard windslabs.>Be aware of thin areas that may propagate to deeper instabilites.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 4

Valid until: Feb 2nd, 2013 2:00PM

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