Avalanche Forecast

Issued: Dec 13th, 2013 4:00PM

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

Brad White, Parks Canada

Banff Yoho Kootenay.

Light snowfalls and strong winds will slowly push the avalanche danger upwards over the next few days. JBW

Summary

Weather Forecast

Another fairly strong pacific storm in a north-westerly flow will bring snow to the Columbias and westerly slopes of the Rockies but only light snow with strong winds to most of the forecast area.

Snowpack Summary

Up to 10 cm new over the past 24 hrs with moderate westerlies have created some touchy thin new wind slabs at treeline and above. The base remains weak with depth hoar and isolated crust near the ground. Drib and drab storm snow combined with wind will be enough to create some natural avalanche activity on steep lee features.

Avalanche Summary

A few thin windslabs have been reported by ski hill avalanche teams. in addition, a natural avalanche ran over a climbing party on Polar Circus yesterday in a near miss with no injuries.

Confidence

Forecast snowfall amounts are uncertain on Saturday

Problems

Wind Slabs

Thin new windslabs exist on steep lee features at TL and above. These slabs are sensitive to triggering, and may step down to the basal depth hoar once triggered. Be aware of the potential for wind to trigger avalanches above climbing routes.

Avoid freshly wind loaded features.Avoid lee and cross-loaded terrain near ridge crests.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Persistent Slabs

The shallow early season snowpack has depth hoar and/or crust at the base and any triggered avalanche will likely step down and involve the entire thickness. A large avalanche with serious consequences is possible.

Be aware of the potential for full depth avalanches due to deeply buried weak layers.Be aware of thin areas that may propogate to deeper instabilites.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Dec 14th, 2013 4:00PM