Avalanche Forecast

Issued: Dec 19th, 2012 4:00PM

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

rupert wedgwood, Parks Canada

Jasper.

Strong winds at ridge top elevations in the Icefields area are increasing the slab avalanche danger.

Summary

Weather Forecast

Strong Southwesterly winds at elevation with the possibility of 10cm of new snow in the Icefields area. Temperatures will remain cool through to the weekend.

Snowpack Summary

Windslabs in the alpine are the primary avalanche concern. These are more likely to be encountered in the Columbia Icefields area where the strongest winds have been observed. In the Marmot Pass area on December 18th, surface slabs failed with a moderate shear near treeline elevations. The mid snowpack remains supportive for the time being.

Avalanche Summary

No new avalanches have been observed in the past 24 hours.

Confidence

Forecast snowfall amounts are uncertain on Thursday

Problems

Wind Slabs

Moderate test results at treeline in the Portal creek area occurred on a Southeast facing 35 degree slope below a 25cm wind slab. Strong SW winds in the Icefields area at upper elevations are likely adding to this condition.

Avoid freshly wind loaded features.Sheltered slopes at lower elevations will offer the best skiing today.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Deep Persistent Slabs

A supportive mid-pack is adding strength to the snowpack above this weakness. Shallow areas should be considered suspect.

Avoid shallow snowpack areas where triggering is more likely.Avoid convexities or areas with a thin or variable snowpack.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely

Expected Size

2 - 3

Valid until: Dec 20th, 2012 4:00PM