Avalanche Forecast

Issued: Jan 9th, 2013 9:29AM

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

mpeter, Avalanche Canada

Purcells.

Very touchy conditions linger. Be aware of overhead hazard and how your position connects to slopes above.

Summary

Confidence

Fair

Weather Forecast

Thursday: Expect mixed skies with some sunny breaks. Temperatures should reach -10 and winds turn to light northerlies.Friday & Saturday: A ridge dominates giving mixed skies, light northerly winds and cool alpine temperatures. Valley cloud is possible.

Avalanche Summary

Explosive and natural avalanches up to 2.0 were observed, predominantly windslab events on north through east facing slopes. Isolated remote and rider triggered slides have also been reported.

Snowpack Summary

The recent storm has brought up to 60cm of new snow to the region. Consistent southwesterly winds have redistributed the new snow (dramatically in some areas) to create widespread windslabbing on lee and open features in the alpine and exposed treeline. Where the wind has been strongest, we have reports of windslabs much lower on slopes than normal.There have been avalanches reported both within the storm layers as well as at the initial storm interface, the January 4th layer. This layer consists of small facets, surface hoar on sheltered treeline and below treeline areas and sun crust on steep south and west facing slopes. The bonds with the facetted snow are improving while the surface hoar / sun crust interface is weak. The midpack is well bonded and strong. The deep crust/facet combo from early November still exists and concern remains (although unlikely) for triggering this layer from a shallow spot.

Problems

Wind Slabs

The consistent strong winds mean that the windslabs extend lower into the terrain than normal.

Stay off recent wind loaded areas until the slope has had a chance to stabilize.>Use ridges or ribs to avoid wind loaded snow.>

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 6

Storm Slabs

Up to 60cm of storm snow has settled into a cohesive slab.

The new snow will require several days to settle and stabilize.>Choose well supported terrain without convexities.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 4

Valid until: Jan 10th, 2013 2:00PM