Avalanche Forecast

Issued: Mar 8th, 2017 4:00PM

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

garth lemke, Parks Canada

Jasper.

March 3rd's 45cm of new 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 night will be cold and 5cm new snow. Thursday will be -16 to -20, light S and W winds, and no new of snow. Friday will be -8, flurries, and light E winds. Saturday will be increasing wind speeds into the 25km/hr range out of the West.

Snowpack Summary

45cm of storm snow from March 3 continues to settle into a soft slab generally at treeline and above. The lower snowpack is structurally weak with depth hoar, facets, and a deteriorating rain crust from November. S aspect we found decomposing SH/surface facet layer on a sun crust down 30cm under March 3rd's storm snow. It was testing unstable.

Avalanche Summary

Skiers on March 7 in Bald hills triggered a size 2 from a km away. Report and pictures can be viewed on CAA's Mountain Information Network. No patrol occurred on March 8.

Confidence

Problems

Persistent Slabs

45cm of storm snow from March 3 has evolved into a soft slab and melded in many locations to the midpack below. South TL aspects the new snow was found resting on a decomposing surface hoar layer on a crust about 30cm down. It tested unstable.

Be wary of slopes that did not previously avalanche.Watch for whumpfing, hollow sounds, and shooting cracks.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

2 - 3

Deep Persistent Slabs

March 3rd 45cm of new snow load produced size 3's. This activity has subsided. They were from the alpine and treeline elevations running to valley bottoms. One should consider it a concern if the persistent slab above is initiated and steps down.

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