Avalanche Forecast

Issued: Dec 1st, 2014 4:00PM

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

patrick jerome, Parks Canada

Banff Yoho Kootenay.

Avalanche control today is still yielding avalanches that have potential to capture, injure and/or bury human riders and climbers. As the temperatures warm this week the risk will increase and conservative terrain choices are highly recommended. PJ

Summary

Weather Forecast

The cold spell of Arctic outflow is being displaced by a warmer air mass.Â Light westerly winds are expected and temperatures will warm up significantly by the weekend so it will be a time to remain cautious and watch rising temperatures and solar warming and their strong influence on the stability of the snowpack.

Snowpack Summary

Recent storm snow has settled into a soft slab and has significant wind affect in open terrain at treeline and above. The lower half of the snowpack is a complex and poorly structured & comprised of the facets (Nov 24th) at the interface of the recent storm snow and a series of thin crusts (Nov 6th) and depth hoar at or slightly above the ground.

Avalanche Summary

Although natural avalanche activity has abated, Banff Visitor Safety performed avalanche control today on the Sunshine access road. Since the end of the storm there have a number of significant natural and explosive results indicating that there remains plenty of potential for human triggering of avalanches that can be large and destructive.

Confidence

Timing or intensity of solar radiation is uncertain on Wednesday

Problems

Deep Persistent Slabs

The primary problem in the snowpack is the interface between the recent storm snow and the November 6th and 24th facet/crust interfaces. This problem is the culprit for the vast majority of the avalanches in the past week. Watch for remote triggers.

Watch for whumpfing, hollow sounds, and shooting cracks.Use conservative route selection, choose moderate angled and supported terrain with low consequence.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

2 - 3

Wind Slabs

The wind affect will be encountered above treeline and above in wind exposed terrain.

Watch for whumpfing, hollow sounds, and shooting cracks.Be careful with wind loaded pockets while approaching and climbing ice routes.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 2

Valid until: Dec 2nd, 2014 4:00PM