Avalanche Forecast

Issued: Jan 7th, 2013 4:00PM

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

ian jackson, Parks Canada

Banff Yoho Kootenay.

The long period of good stability is ending. The Jan. 6th layer will likely be touchy for some time. Moderate alpine winds on Tues will keep the alpine hazard elevated, and a large snowfall on Tues PM/ Wed will raise the hazard significantly.

Summary

Weather Forecast

Tues: Alpine temps -10/-15. Alpine winds mod to strong SW. 2-4 cms new snow.Tues overnight and Wed: Alpine temps -10/-15. Alpine winds mod W. 20-35 cms new snow!!Thurs: Alpine temps -15/-20. Alpine winds becoming light N. Clearing skies.

Snowpack Summary

5-30 cm of new snow overlies the Jan. 6th interface which is either a facet, surface hoar, or hard slab layer. Moderate S/SW winds have created soft slabs in exposed alpine and treeline areas. Field reports say these new slabs range from touchy to stubborn to trigger. The lower snowpack is facetted E of the divide and well settled to the W.

Avalanche Summary

A helicopter bombing mission on the sunshine road today produced minimal results to size 2, mostly being loose dry avalanches in the facets. The ski hills are reporting ski cutting newly formed soft slabs to size 1 and newly formed cornices.

Confidence

Forecast snowfall amounts are uncertain

Problems

Wind Slabs

New snow and moderate wind from the West have started to create wind slabs in alpine lee areas. This problem is more prominent W of the divide where more snow has fallen. Expect these wind slabs to be reactive to skier traffic.

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

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

Elevations: Alpine.

Likelihood

Likely - Very Likely

Expected Size

1 - 2

Loose Dry

Steep gully features with shallow snow packs are the likely areas to run into this problem. This problem is most prominent in ice climbing terrain where a small new snow sluff could entrain the facets and push a climber off their feet.

Be cautious of sluffing in steep terrain.Avoid ice climbs that are in terrain traps below large start zones.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Jan 8th, 2013 4:00PM