Avalanche Forecast

Issued: Mar 22nd, 2012 4:00PM

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

pmarshall, Avalanche Canada

Northwest Inland.

The avalanche danger could be a little higher during the day with warmer temperatures and strong solar radiation.

Summary

Confidence

Fair - Due to limited field observations

Weather Forecast

A ridge of high pressure should maintain mostly sunny and dry conditions for the next several days. The freezing level will drop to valley bottom overnight and rise to 800-1000m during the day. Ridge top winds should be generally light from the south.

Avalanche Summary

No new slab avalanches have been reported in the past day or two, although observations are limited. Loose dry sluffing was observed in steep terrain. There were also a few reports of cornice failures on the weekend, but most did not trigger slabs.

Snowpack Summary

Up to 25cm of new snow covers the previous surface which included a sun crust on southerly aspects, surface facets or surface hoar in cool shady areas, and pockets of wind slab in exposed terrain. Moderate southerly winds have created new wind slabs in lee and cross-loaded terrain. The mid February persistent weak layer interface, comprised of spotty surface hoar, facets and crusts, is buried 80-120 cm below the surface. No recent activity has been reported on this interface. However, recent snowpack tests have been giving hard but sudden "pop" results and indicate it is has the potential to react given the right trigger in the right place. For route selection, it should still be on your radar and is more likely to be triggered on steeper, unsupported terrain. Cornices in the area are reported to be very large and primed for natural collapse or triggering by a person.

Problems

Wind Slabs

New wind slabs may be triggered in exposed lee and cross-loaded features.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Cornices

Large cornices exist in alpine terrain. A failure could be destructive by itself, and could also trigger an avalanche on the slope below.

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

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1 - 6

Loose Wet

Loose wet avalanches are likely in steep south-facing terrain if the sun is shining.

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

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Valid until: Mar 23rd, 2012 9:00AM