Avalanche Forecast

Issued: Apr 2nd, 2014 4:41PM

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

grant statham, Parks Canada

Banff Yoho Kootenay.

It's an uneasy time for avalanche prediction now because in some areas the danger is Low, while in others the danger is Considerable - meanwhile the ski quality is excellent. Be wary, we have seen at least one large avalanche every day this week.

Summary

Weather Forecast

Another storm is heading our way and should move into the region by mid-morning on Thursday. Expect strong westerly winds on the leading edge of the storm, with 10-15 cm expected by Friday. Temperatures should remain below freezing, except if the sunshine pokes through when suddenly things will feel really hot.

Snowpack Summary

Huge and important differences exist across the region now. Western areas such as Emerald and Field have a deep and stable snowpack. Contrast this with the Lake Louise and Sunshine areas, where the weaker snowpack is showing signs that the ground level layer of weak facets is waking up again - slowly. This layer has been dormant since February.

Avalanche Summary

Two new avalanches reported today - a size 2.5 failed on the ground layer from an explosive at the Lake Louise ski area, and a cornice failure on Mt. Rundle triggered an avalanche in the afternoon. Yesterday 4 separate avalanches were reported to have failed on the ground in shallow snowpack areas.

Confidence

Problems

Deep Persistent Slabs

The ground level weakness of facets and depth hoar appears to have woken up, and the main avalanche problem right now is occasional large avalanches failing on the ground. Avoid, or carefully select any large steep slopes at treeline or above.

Avoid shallow snowpack areas where triggering is more likely.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 4

Wind Slabs

Strong winds in front of Thursday's storm, combined with another 10cm of snow will make for small, but touchy windslab conditions at the higher elevations by mid to late afternoon on Thursday.

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

Aspects: North, North East, East.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Apr 3rd, 2014 4:00PM