Avalanche Forecast

Issued: Dec 19th, 2011 4:51PM

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

landon shepherd, Parks Canada

Jasper.

Strong to extreme winds coupled with warm temperatures are creating hard, easily-triggered windslabs in most treeline lee features as well as pockets of the alpine that are sheltered enough to hold snow.

Summary

Weather Forecast

Snowpack Summary

Avalanche Summary

Confidence

Wind effect is extremely variable

Problems

Wind Slabs

Windslabs have formed in sheltered lee features at Treeline and protected pockets in the Alpine.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Deep Persistent Slabs

Basal facet collapses are still being noted in test pits below midpack bridging layers. Shallow snowpack areas and rocky outcrops are likely trigger locations.

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Storm Slabs

Anywhere from 5-35cm of new snow fell Saturday evening. Warm temperatures and winds have stiffened the storm snow into a more cohesive soft slab layer. Some pockets of soft slab may release from skier presence.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Dec 20th, 2011 4:00PM