Avalanche Forecast

Issued: Nov 28th, 2017 4:00PM

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

grant statham, Parks Canada

Banff Yoho Kootenay.

Avalanche activity has settled down slightly with the cooler temperatures, and the ski quality is good - dry snow on a supportive crust right down into the trees. We remain concerned about human triggering and are avoiding avalanche starting areas.

Summary

Weather Forecast

A strong SW flow over the mountains will create favorable conditions for heavy snow along Hwy 93N Icefields Parkway. Snow will continue Tuesday evening over the higher elevations and end near midnight. 10-20cm is possible by Wednesday morning. The heaviest snowfall will be from Sask River Crossing to the southern sections of the Jasper region.

Snowpack Summary

Another 10-15cm of new snow overnight on Tues brings to the 5-day dry storm snow amount to 40cm. Moderate winds have been transporting this snow, but windslab formation has been limited in the past 24 hours. The main weakness to watch is the Oct 31 crust/facet layer located about 30cm above the ground which produces easy, planar shear test results.

Avalanche Summary

No avalanches were reported or observed today, but visibility was limited.

Confidence

Wind effect is extremely variable

Problems

Persistent Slabs

Although the snowpack is strong, it remains unstable in many alpine/treeline areas. Avoid avalanche starting zone areas. We do not expect natural avalanches on this layer in the next 24-hrs, but human triggering remains a serious concern.

Use conservative route selection, choose moderate angled and supported terrain with low consequence.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Wind Slabs

Up to 20cm is possible by Wed making for a weekly total of 40cm dry snow to be blown into windslabs. We expect these to only be a problem at the higher elevations where they can be easily triggered by skiers in leeward areas.

Use caution in lee areas. Recent wind loading has created wind slabs.

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

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Nov 29th, 2017 4:00PM