Avalanche Forecast

Issued: Jan 2nd, 2013 4:04PM

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

ian jackson, Parks Canada

Banff Yoho Kootenay.

An inversion is creating warm alpine temperatures even though it is cold in the valleys. This, combined with moderate to strong SW/W winds will raise the hazard on Thursday.

Summary

Weather Forecast

Thurs: Inversion with alpine temps in the 0 /-5 range. M-S SW/ W alpine winds. Clear skies.Fri: Inversion breaks down. Alpine temps -10/-15. M-S W/NW alpine winds. Overcast with possibility of 1-2cms.Sat: Alpine temps -5/-10. L-M SW alpine winds. Clear skies.

Snowpack Summary

Hard wind slabs exist in exposed alpine features but haven't been reactive to skier traffic. Suface hoar is growing in sheltered treeline locations. W of the divide, a well settled snowpack exists with the basal Nov 6 crust well bonded. In the front ranges E of the divide, a facetted snowpack exists with the Nov 6 basal crust being mainly facetted.

Avalanche Summary

No new avalanche activity.

Confidence

Wind speed and direction is uncertain on Friday

Problems

Wind Slabs

Localized moderate winds have created hard windslabs in exposed alpine terrain. Although these have not been reactive to human traffic, they may become more reactive as the alpine temps increase.

Be cautious as you transition into wind affected terrain.

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Loose Dry

This problem exists mainly in thin snowpack areas E of the divide where the snowpack has completely facetted and lost all cohesion. Watch for sloughing in steep terrain where the snow is unsupportive, particularly as temps increase.

Carefully evaluate and use caution around thin snowpack areas.Be cautious of sluffing in steep terrain.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 2

Cornices

The cold temperatures are facetting out cornices and large cornice failures have been observed. Although the cornice failures have not been triggering slabs on the slopes below, the cornice chunks themselves would definitely hurt if they hit you

Pay attention to overhead hazards like cornices.Give cornices a wide berth when travelling on or below ridges.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Jan 3rd, 2013 4:00PM