Avalanche Forecast

Issued: Apr 12th, 2013 4:00PM

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

max darrah, Parks Canada

Jasper.

Significant snowfall is expected for the Columbia Icefield area - conservative terrain choices are advised until the snow has a chance to stabilize.

Summary

Weather Forecast

Weather models show the Columbia Icefield area receiving steady snowfall for the weekend, with up to 25cm total by Sunday night.Â Winds should remain light SW below 2000m, but will be gusting in the strong range (SW-NW) in the alpine. Temps remaining cool and freezing levels below 1300m.

Snowpack Summary

Windslabs on lee aspects (NE) of exposed ridgecrests above treeline are covered by 5-10cm of new snow. New snow is sitting on previous temperature crusts below 2100m and on sun crust on solar aspects. Cornices are big and heavy, and several natural cornice falls have been observed in the past few days. Melt freeze crust carries well in AM.

Avalanche Summary

No new avalanches observed today, but several large cornice failures reported in the past 48hrs.Â Of note, several of these cornice falls did trigger deep persistent slabs with crown fracture depths of up to 1m, and some were observed to have triggered more recent storm/wind slabs with a depth of 10-40cm.Â Â Â

Confidence

Intensity of incoming weather systems is uncertain

Problems

Storm Slabs

The primary concern is where new storm slabs are sitting on previous crusts,in which case they may be triggered by light loads. Existing windslabs on lee aspects will also become more sensitive to triggering with the increased load from the new snow.

The new snow will require several days to settle and stabilize.Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Cornices

Several cornice failures were observed in the past 48 hours and some of these did trigger storm slabs on the slopes below up to size 2.

Avoid steep slopes below cornices.Stay well to the windward side of corniced ridges.

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 3

Valid until: Apr 13th, 2013 4:00PM