Avalanche Forecast

Issued: Apr 20th, 2013 4:00PM

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

chris gooliaff, Parks Canada

Banff Yoho Kootenay.

It is still wintery in the high alpine. Isolated wind slabs can be expected, and may be hidden by the new, light dusting we are currently receiving.

Summary

Weather Forecast

An upslope flow will bring cloudy conditions and light snow to the region tomorrow. Ridge-top winds will be light/moderate from the N/NE and freezing levels will remain in the valley bottom.

Snowpack Summary

Cooler conditions for the next few days should create a solid, supportive crust in the morning, softening with day-time warming. There are areas of wind effect in the alpine and isolated wind slabs can be expected in lee areas above 2400 m. These slabs can be triggered on steep, unsupported slopes.

Avalanche Summary

Yesterday, a field team on the South side of Mt. Patterson ski cut a size 1 thin avalanche out of 45 degree terrain at 3100m today. On Thursday near Unity Peak in the Lake Louise backcountry, a size 1.5-2 skier-triggered avalanche near 2500m was reported. The slide was 50cm thick and 80m wide, which apparently slid on a crust on a SE aspect.

Confidence

Problems

Wind Slabs

Moderate winds have created areas of thin wind slabs in lee areas above 2400 m. These slabs were more sensitive to triggering Friday with warmer temperatures, but will likely be more stubborn with the forecasted cooler weather.

Be cautious as you transition into wind affected terrain.Start and finish early before the surface crusts melt.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Apr 21st, 2013 4:00PM