Avalanche Forecast

Issued: Mar 25th, 2017 4:00PM

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

a.l. horton, Parks Canada

Jasper.

Avoid all big avalanche terrain that hasn't recently run. The deep persistent slab is easily triggered from weak spots resulting in large full path avalanches.

Summary

Weather Forecast

Continued cool temps into next week with light flurries and SW winds. Cloudy skies with sun expected on Tuesday.

Snowpack Summary

The main concern in the snowpack at tree-line and above is the deep persistent slab over weak facet layer at ground. This slab can be triggered by travelers from shallow or weak locations or naturally from large loads such as cornice failure or windslab avalanches. All steep loaded slopes that have not recently avalanched should be avoided.

Avalanche Summary

A size 3 skier accidental slab avalanche was reported Saturday afternoon north of the Icefields on a NE aspect at tree-line. The avalanche was triggered from below as group worked their way through the trees. It was triggered from a whumph and propagated wide and ran to ground. One member was partially buried with no injuries.

Confidence

Due to the number and quality of field observations on Sunday

Problems

Deep Persistent Slabs

The deep persistent slab can be triggered by travelers from shallow or weak locations or naturally from large loads such as cornice failure or windslab avalanches. On Mar 25, skiers triggered a sz 3 on this layer.

Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.Avoid paths that have not avalanched recently.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 4

Wind Slabs

Windslabs exist at treeline and above on lee aspects. No recent natural activity has been observed however human triggering is possible.

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

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 3

Cornices

Large cornices on ridge top lee features. Recent cornice failure has triggered large avalanches from alpine terrain.

Pay attention to overhead hazards like cornices which could easily trigger the deep persistent slab.Give cornices a wide berth when travelling on or below ridges.

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

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1 - 3

Valid until: Mar 26th, 2017 4:00PM