Avalanche Forecast

Issued: Dec 10th, 2016 4:37PM

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

Ruari Macfarlane, Parks Canada

Waterton Lakes.

Change is in the air: Strong Westerly winds on Saturday night through Sunday are set to transform powder snow into variable, slabby conditions. Avoid steep lee slopes. Seek sheltered areas for great turns, but watch for lurking logs & stumps.

Summary

Weather Forecast

On Sunday, a low stalled on the coast sends us it's wishes: expect warmer temperatures (-10 at treeline), strong Westerlies, and flurries. 5cm of new snowfall on Sunday night as winds drop may bury Wind Slabs. Monday sees a triumph of the Arctic ridge. Sunshine and Light winds predominate on Monday and Tuesday, with temperatures from -15 to -24.

Snowpack Summary

30cm of low density snow is being redistributed into Wind Slabs. The snowpack above 2000m is over 100cm deep in the West, but much shallower at lower elevations, and in Eastern areas. A crust from Mid-November is buried near the bottom of the snowpack. In some areas, cold temperatures have weakened this crust, which is worthy of consideration.

Avalanche Summary

Widespread spindrift was observed in steep wind-exposed terrain on Saturday afternoon. It is likely loose snow avalanche activity was occurring in similar areas .

Confidence

Due to the number and quality of field observations

Problems

Wind Slabs

This problem began developing on Saturday afternoon, and will increase during Sunday with forecast strong winds. There is plenty of low-density snow available for transport.

The recent snow may now be hiding windslabs that were easily visible before the snow fell.Use caution in lee areas. Recent wind loading has created wind slabs.

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

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

2 - 2

Loose Dry

This will mainly be a problem on Sunday as wind moves low-density snow around.

Be very cautious with gully features.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Dec 13th, 2016 4:00PM