Avalanche Forecast

Issued: Apr 3rd, 2014 4:00PM

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.

stephen holeczi, Parks Canada

Banff Yoho Kootenay.

Excellent ski quality on N aspects. Avoid thin snowpack areas where the basal layers can be triggered. SH

Summary

Weather Forecast

The sun should not be a large factor over the next couple days. Up to 10cm is expected thursday night through Friday with temperatures staying fairly cool in the alpine (-10C at 3000m) and highs of around 0C at valley bottom. Westerly winds will pick up tonight into Friday gusting as strong as 75 km/h in alpine areas.

Snowpack Summary

Western areas such as Emerald and Field have a deep and stable snowpack. Contrast this with the Lake Louise and Sunshine areas, where a weaker snowpack is showing signs that the ground level layer of facets is waking up again - slowly. This layer has been dormant since February. A crust exists on all but N aspects.

Avalanche Summary

Lake Louise avalanche safety was reporting large whumpfs in shallow alpine areas today. A profile on one of these slopes found very easy compression results on the basal depth hoar. Yesterday a size 2.5 failed on the ground from an explosive at the Lake Louise ski area, and a cornice failure on Mt. Rundle triggered an avalanche in the afternoon.

Confidence

Problems

Deep Persistent Slabs

We have seen isolated activity on depth hoar and facets located near the base of the snowpack in thin areas mainly E of the divide. The main problem right now is triggering the occasional large avalanche that fails on the ground.

Avoid shallow snowpack areas where triggering is more likely.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Wind Slabs

With increased winds and some snow in the forecast, watch for wind slab formation in the lees of ridge crests over the next 24 hours.

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

Aspects: North, North East, East.

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Apr 4th, 2014 4:00PM