Avalanche Forecast

Issued: Apr 12th, 2015 4:00PM

The alpine rating is below threshold, the treeline rating is below threshold, and the below treeline rating is below threshold. Known problems include Wind Slabs and Cornices.

aaron beardmore, Parks Canada

Banff Yoho Kootenay.

Strong wind today is creating wind slabs at ridge crest in lee areas. Please read the explanation for spring conditions here.

Summary

Weather Forecast

Cool temps (-12 to -15 @ 3000m) and very light snow fall is expected over the next three days. Wind will remain strong at high elevations from the NW until late Monday.

Snowpack Summary

20-30cm of new snow over the weekend with gusty SW through NW winds has created wind slabs in lee areas above treeline. The new snow sits on a firm crust on solar aspects up to ridge crests and up to 2300m on N aspects. This buried crust provides a bridge over the basal facets which remain dormant.

Avalanche Summary

No avalanches observed or reported but the potential for triggering wind-slabs at ridge crest is definitely there today.

Confidence

Problems

Wind Slabs

Strong wind from the NW has created wind slabs on lee aspects up to 50cm thick. These are reactive to skier traffic and have been failing naturally in some locations. Expect sluffing in any steep terrain as well.

Be cautious of sluffing in steep terrain.Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

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

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1 - 2

Cornices

There have been many reports of cornice chunks falling off of ridge crests which may be big enough a load to trigger an avalanche on the basal facets, or be enough mass to be a hazard themselves.

Cornices become weak with daytime heating, so travel early on exposed slopes.Stay well back from cornices.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 3

Valid until: Apr 13th, 2015 4:00PM