Avalanche Forecast

Issued: Dec 3rd, 2012 4:23PM

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

brian webster, Parks Canada

Banff Yoho Kootenay.

Summary

Weather Forecast

Continued unsettled weather with light accumulations through Wednesday. Strong SW winds forecast for Tuesday will increase the avalanche hazard.

Snowpack Summary

30-40 cm of accumulated storm snow over the last 5 days in addition to moderate SW winds have created soft slabs in many lee alpine locations. These slabs are reactive to skier triggering. The November 6 raincrust is down 80 cm and remains a concern.

Avalanche Summary

Numerous Class 1-1.5 ski cut slabs in the alpine (25-40 cm deep) were reported by Sunshine ski patrol today. Yesterday climbers reported a sizable slide on Polar Circus ice climb running down to below the pencil feature.

Confidence

Due to the number and quality of field observations

Problems

Wind Slabs

Moderate SW winds and lots of snow available for transport has created touchy wind slabs in the alpine. Forecasted strong winds for Tuesday will exasperate the slab development and increase the avalanche hazard.

Avoid freshly wind loaded features.Be cautious as you transition into wind affected terrain.

Aspects: North, North East, East, South East, South.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Persistent Slabs

While it is unlikely, triggering this layer is still possible. It is located 50-90cm below the surface. Use caution and consider this layer when venturing into larger terrain.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 3

Valid until: Dec 4th, 2012 4:00PM