Avalanche Forecast

Issued: Dec 19th, 2016 8:08AM

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

Percy Woods, Parks Canada

Glacier.

Storm snow along with moderate winds and a weak old snow surface has pushed us into HIGH. Stick to simple terrain.

Summary

Weather Forecast

30cm of storm snow have fallen at 1900m and depending on forecast another 15cm is expected today. Alpine temperature should rise to -11C with winds in the moderate gusting to strong range. The outlook for Tuesday is another pulse of moisture with 11cm forecast along with warming temperatures and moderate west wind.

Snowpack Summary

30cm+ of storm snow overnight at 1900m with another 15cm on route today. Moderate gusting to strong SW winds will be redistributing the storm snow onto alpine and treeline lee and crossloaded features forming soft slabs. The other key ingredient is the weak facetted old snow surface. This combo should lead to easily triggered surface soft slabs.

Avalanche Summary

We are expecting an avalanche cycle has started overnight and will continue through the day today. Slides will be in the form of both soft slab and loose dry slides when the weak facetted old snow surface gets overloaded.

Confidence

Forecast snowfall amounts are uncertain

Problems

Storm Slabs

30cm of storm snow is settling over a very weak old surface of facetted snow. The surface slab will be sensitive to human and natural triggering especially in areas of wind effect as it overloads the weak layer.

The new snow will require several days to settle and stabilize.Use conservative route selection, choose moderate angled and supported terrain with low consequence.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

1 - 3

Loose Dry

Sunday afternoon we were already observing loose dry snow sluffing as the weak old snow surface was overloaded. Add another 30cm overnight and these slides could entrain enough mass to be an issue for skiers and riders.

Use caution above cliffs where small avalanches may have severe consequences.Be aware of party members below you that may be exposed to your sluffs.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Dec 20th, 2016 8:00AM