Avalanche Forecast

Issued: Dec 8th, 2011 4:00PM

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

Brad White, Parks Canada

Banff Yoho Kootenay.

The snowpack is starting to bridge the weak base of depth hoar over crust, but human triggering in steep terrain is still likely. Warming over the weekend may create an inversion with near zero temperatures in the alpine.JBW

Summary

Weather Forecast

Snowpack Summary

Avalanche Summary

Confidence

Problems

Deep Persistent Slabs

The weak base of depth hoar and facets is now less sensitive to human triggering , however skier triggered and natural avalanches have recently been observed on this layer. A natural with a 400 m crown was observed on Mt Lefroy yesterday.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 3

Wind Slabs

Wind effect in the alpine and at treeline has created a hard slab on most lee slopes. This slab can be triggered from the edges or thin spots and will likely immediately step down to the weak base of depth hoar.