Avalanche Forecast

Issued: Mar 7th, 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.

garth lemke, Parks Canada

Jasper.

The weekends 45cm storm snow continues to settle. Choose simple terrain that is well supported. A buried unstable surface hoar layer was found on South aspect at treeline sitting on a crust. Be cognisant of this.

Summary

Weather Forecast

Wednesday and Thursday will be -10 to -18, 5-10cm of snow, and light South and West winds shifting Easterly on Thursday. Temperatures will drop to -20 on Thursday then warm up on Friday.

Snowpack Summary

45cm of storm snow from Friday and Saturday arrived with light and some moderate southerly winds. It continues to settle into a soft slab at treeline and above. The mid and lower snowpack is structurally weak, the base of which is 5mm depth hoar crystals and a deteriorating rain crust. S aspect found decomposing SH layer down 30 under storm snow.

Avalanche Summary

Tuesday noted two recent size 3's on Kitchener slopes facing highway. They were wide and ran far. Avalanche control work on Sunday produced up to sz 3, some stepping down to deep persistent layers or to the ground where weak facets and depth hoar exist.Â

Confidence

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

Possible - 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 8th, 2017 4:00PM