Avalanche Forecast

Issued: Mar 27th, 2016 4:00PM

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

aaron beardmore, Parks Canada

Banff Yoho Kootenay.

http://www.pc.gc.ca/apps/scond/Cond_E.asp?oID=23022&oPark=100092A Special Avalanche Warning is in effect as we do not think the danger rating of MODERATE adequately illustrates the complexity in the snowpack right now. This is a low probability, high consequence period with a highly variable snowpack.

Summary

Weather Forecast

Cloud cover and below surface freezing levels are expected in the next 2 days. Very light precip amounts are expected to accompany the cloud cover (~8mm). Upper level wind will shift to come from the N-NE.

Snowpack Summary

A thin melt/freeze crust exists on solar aspects, and on shady aspects up to 2000m where it disappears. Dry snow exists mainly on N aspects only. Shallow snowpack areas are weak, and we are concerned about facets in the lower snowpack overlain by a stiff slab which produces easy, sudden collapses in tests.

Avalanche Summary

No avalanches observed or reported today.

Confidence

Due to the number and quality of field observations on Sunday

Problems

Deep Persistent Slabs

Deep facet layers remain very weak, especially in thin or rocky areas. Avoid large open slopes, steep slopes (>30 degrees) and be wary that you can trigger this problem from a long distance away - the slab is stiff and it propagates far.

Avoid slopes when the solar radiation is strong, especially if they have large cornices overhead.Avoid steep convexities or areas with a thin or variable snowpack.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 4

Cornices

Cornices are large. Ensure you give them a wide berth on ridge crests, as they can pull back a long way when they fail and may trigger avalanches below. If you need to travel under cornices - move quickly.

Pay attention to overhead hazards like cornices which could easily trigger the deep persistent slab.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 3

Valid until: Mar 28th, 2016 4:00PM