Avalanche Forecast

Issued: Mar 14th, 2013 4:00PM

The alpine rating is high, the treeline rating is considerable, and the below treeline rating is considerable. Known problems include Storm Slabs, Wind Slabs and Loose Wet.

chris gooliaff, Parks Canada

Banff Yoho Kootenay.

Cooler temp's will help bring the danger levels down, but it will take a few days for the new snow to stabilize at all elevations. Use conservative terrain choices.

Summary

Weather Forecast

The snow will ease off tomorrow and we should see freezing levels drop to 1200m by the end of the day. Winds will also decrease to moderate from the west. We may even see broken, patchy clouds east of the Divide. Saturday may bring another disturbance, with convective cells bringing light snow, moderate gusty winds, and a further drop in temp's.

Snowpack Summary

Up to 50cm of storm snow has fallen in the last 2 days, with higher amounts observed west of the Divide and up Hwy 93N. Storm slabs have formed on the surface and are bonded poorly to the older surfaces. Below tree-line, the rain has saturated the surface layers and created very unstable conditions.

Avalanche Summary

Lots of natural activity observed today, especially below tree-line in Yoho. Numerous deep, wet slabs to size 3 were seen failing and running to the valley floor. A party of 3 skiers in the Lake Louise backcountry remotely triggered a size 2 slab avalanche from 100m away, 50-60cm deep, 40m wide, and running 200m.

Confidence

Due to the number of field observations

Problems

Storm Slabs

40-60cm storm slabs are poorly bonded to older surfaces. Touchy conditions at all elevations.

The new snow will require several days to settle and stabilize.Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 3

Wind Slabs

Strong W winds are developing wind slabs on lee aspects and will be sensitive to human triggering.

Avoid freshly wind loaded features.

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 3

Loose Wet

Rain to 1900m has created unstable conditions below tree-line. Travel is not recommended until the temperatures cool down.

Difficult travel conditions.Ensure everyone has essential avalanche gear and knows how to use it.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Likely

Expected Size

1 - 3

Valid until: Mar 15th, 2013 4:00PM