Avalanche Forecast

Issued: Dec 17th, 2013 4:28PM

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

snow safety, Parks Canada

Banff Yoho Kootenay.

Avalanche Control is planned for the Sunshine Road tomorrow. No skiing or climbing on Bourgeau or the Eagles. JBW

Summary

Weather Forecast

Another storm tonite will bring possibly 5-10 cm followed by cold temperatures with a brief arctic air outbreak. Another storm will moderate temperatures by the weekend.

Snowpack Summary

Approximately 25 cm storm snow with strong south-westerlies over the last two days has created touchy wind slabs in all open areas above treeline. Windward slopes are scoured. bare. The mid pack remains strong enough to support most places where the snowpack is deeper than 60cm. The base is weak DH. Isolated SH at treeline beneath storm snow.

Avalanche Summary

A fresh size 2.5 was observed above Bourgeau Right Hand Waterfall that ran down to the edge of the cliffs. The crown was blown in beneath the cornice but suspect storm snow snow slab with wind loading as the trigger.

Confidence

Forecast snowfall amounts are uncertain

Problems

Wind Slabs

20-40cm storm snow over the past few days has been moved by strong westerly winds creating fresh, touchy slabs on steep lee features.

Avoid freshly wind loaded features.Avoid steep slopes below cornices.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Deep Persistent Slabs

Many of the recent avalanches have been stepping down or failing at the base of the snowpack on the early season weak base..

Be aware of the potential for full depth avalanches due to deeply buried weak layers.Choose conservative lines and watch for clues of instability.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Dec 18th, 2013 4:00PM