Avalanche Forecast

Issued: Mar 5th, 2017 4:00PM

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

mark herbison, Parks Canada

Jasper.

Avalanche control along the Icefields Parkway produced results up to size 3. The recent storm snow is stressing the snowpack and will require some time to stabilize, choose simple terrain that is well supported.

Summary

Weather Forecast

Periods of light snow with accumulations up to 2cm by Monday evening. Winds are forecasted to be light from the Southwest with temps ranging from -10 to -16.

Snowpack Summary

40cm of settling HST in the last 2 days came in under the influence of mostly light, with some moderate southerly winds. Soft slab forming at treeline and above. The mid and lower snowpack is structurally weak, the base of which is large (5mm) depth hoar crystals and a deteriorating rain crust.

Avalanche Summary

Avalanche control work produced results up to sz 3, some of which stepped down to deep persistent layers or to the ground where weak facets and depth hoar exist. Natural activity was most prevalent in the alpine and similar to the control work, was stepping down, resulting in deep releases, sz 2-3.

Confidence

Due to the number and quality of field observations on Sunday

Problems

Storm Slabs

40cm of storm snow is forming a soft slab at treeline and above. It will remain reactive to triggering for the next few days. Where stronger winds in the alpine have transported the snow it may be up to 60cm thick.

If triggered the storm slabs may step down to deeper layers resulting in large avalanches.Use caution in lee areas in the alpine and treeline. Storm snow is forming touchy slabs.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Deep Persistent Slabs

Increased loading above this layer from the recent storm snow has produced a number of releases up to size 3. These are mostly from the alpine and treeline elevations and are running down to the valley bottoms.

Use conservative route selection, choose moderate angled and supported terrain with low consequence.Use caution on open slopes and convex rolls

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

2 - 3

Persistent Slabs

Increased loading on this layer from the recent storm snow has produced a number of releases up to size 3. Triggering is mostly likely from shallower locations around rocky terrain.

Be wary of slopes that did not previously avalanche.Be aware of the potential for wide propagations.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 3

Valid until: Mar 6th, 2017 4:00PM