Avalanche Forecast

Issued: Dec 28th, 2011 4:00PM

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

marc ledwidge, Parks Canada

Banff Yoho Kootenay.

The storm is forecasted to intensify tonight with continuing moderate to strong winds. Natural activity in the alpine is expected to be more widespread.

Summary

Weather Forecast

Snowpack Summary

Avalanche Summary

Confidence

Forecast snowfall amounts are uncertain on Thursday

Problems

Wind Slabs

In most areas, storm snow amounts are now about 30 to 40 cm. SW winds have created soft slabs up to 50 cm deep. These are touchy and are running long distances.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Deep Persistent Slabs

Although there has been little recent avalanche activity on this layer, it could become active with the current additional loading. On a larger feature, a windslab release has the potential to step down into these facets.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Storm Slabs

Distribution of the December 10 buried surface hoar layer is spotty but mostly on the west side of the Divide. Isolated soft slabs on this layer were triggered as early as yesterday in the Yoho Valley at tree-line.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Dec 29th, 2011 4:00PM