Avalanche Forecast

Issued: Nov 30th, 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.

The snowpack is in an immature state at the moment. Field technicians today observed consistent whumphing while traveling on skis below treeline suggesting the snowpack is ripe for failure. Remain cautious when evaluating and selecting your terrain.

Summary

Weather Forecast

A strong high pressure system will remain in place for the next 48 hours creating arctic outflow conditions and very cold temps. Temperature should moderate by mid week.

Snowpack Summary

Recent storm snow has settled into a soft slab but the snowpack character at the moment is unconsolidated and lacking any structure. Field forecasters were penetrating through the entire snowpack with skis close to the ground. Observed is the prominent Nov 6th crust which lies 10-20 cm's above the ground and snowpack tests yielded sudden collapses.

Avalanche Summary

The eastern rockies have seen the first major avalanche cycle this winter. Numerous avalanches up to size 3 were observed in the Alpine and Treeline on all aspects and many failures took place during the peak of the storm.

Confidence

Due to the number of field observations on Sunday

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.

Be aware of the potential for wide propagations.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

Likely areas to encounter this problem exist in open areas of terrain above treeline in the lee of the wind.

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

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 2

Valid until: Dec 1st, 2014 4:00PM