Avalanche Forecast

Issued: Mar 19th, 2014 4:00PM

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.

Summary

Weather Forecast

Snowfall starting Wednesday night, continuing through the weekend, reaching 25cm in both the Maligne Lake area and Columbia Icefields area by Sunday night. Winds to remain relatively light but shifting in direction. Temps cool with good overnight recovery and freezing levels remaining below 1000m.

Snowpack Summary

30cm settled storm snow over a variety of surfaces. Drought layer (Feb 10) down 50-80cm. 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

Due to the number of field observations

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 snow available for transport, we suspect recent windslab formation in the alpine in exposed areas.

Be careful with wind loaded pockets while approaching and climbing ice routes.The recent snow may now be hiding windslabs that were easily visible before the snow fell.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

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 20th, 2014 4:00PM