Avalanche Forecast

Issued: Mar 18th, 2014 4:07PM

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

max darrah, Parks Canada

Jasper.

Careful snowpack evaluation and cautious route finding is essential right now.

Summary

Weather Forecast

Temps to remain cool, freezing levels well below treeline, and winds light to moderate from the Southwest. Light snowfall expected to begin on Wednesday, intensifying towards the weekend. The Columbia Icefields area will receive an additional 25cm by Sunday.

Snowpack Summary

The Columbia Icefields received 35cm of low density snow over the weekend. Prior to that the alpine was found to be scoured old snow or hard windslabs. Lots of snow available for transport, and some moderate ridge top transport observed today.

Avalanche Summary

Field patrols in the past few days observed the debris from numerous large avalanches. These avalanches exhibited wide propagation, were primarily found in big East facing alpine terrain, and several were triggered by cornice fall. As the wind begins to push the recent snow around, the likelihood of triggering new slabs will increase.

Confidence

Intensity of incoming weather systems is uncertain

Problems

Persistent Slabs

The "drought layer" (Feb 10) has been sensitive in the past week, contributing to numerous large avalanches. Pay particular attention to moraines at treeline and crossloaded features in the alpine.

Be aware of thin areas that may propogate to deeper instabilites.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Wind Slabs

With lots of new snow available for transport, new windslabs will be forming in exposed areas as the winds increase in the next couple of days.

Caution in lee and cross-loaded terrain near ridge crests.Use caution in lee areas in the alpine. Recent wind loading have created wind slabs.

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

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1 - 3

Storm Slabs

35cm of recent snow is settling rapidly. Although this snow appears to be bonding well, caution is warranted in steep terrain. It is a good idea to test the storm snow interface prior to committing to your line.

If triggered the storm slabs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Mar 19th, 2014 4:00PM