Avalanche Forecast

Issued: Apr 21st, 2012 4:00PM

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

jeremy.mackenzie, Alberta Parks

Kananaskis.

Very high freezing levels expected over the next few days (up to 3100m). Avalanche danger will be largely dependent on the quality of the overnight freeze. Spring-time conditions call for early starts and early finishes.

Summary

Confidence

Good

Weather Forecast

Variable cloud will push into the region on Sunday, with moderate to strong SW winds. Temperatures will climb and freezing levels are forecasted to hit 3100m. No precipitation is expected.

Avalanche Summary

A few solar triggered loose snow avalanches were observed on steep solar aspects today.

Snowpack Summary

Well settled spring snowpack with crusts on all aspects and elevations except true north aspects where crusts exist below 2400m on average. Melt-freeze cycles occurring daily and the snowpack continues to settle. Isolated pockets of wind slab up to 30cm deep are found in cross loaded terrain and immediately below ridgeline on lee features in the alpine. Cornices are sagging in some locations.

Problems

Loose Wet

Crusts are breaking down each day as the temperature warms up. Decreases in stability will first appear on solar aspects then spread to all aspects as temperatures climb. Keep an eye on overhead terrain that is already in the sun.

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

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 4

Wind Slabs

Pockets of wind slab have developed in lee and cross loaded terrain at treeline and above. Field observations are showing that these slabs do not extend far downslope. Some isolated natural avalanche activity is associated with this problem.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Deep Persistent Slabs

A few warm days may re-awaken some of the deeply buried weak layers lingering at the base of the snowpack. There has been no recent activity on this layer but that could change will the big pulse of heat forecasted for the next two days.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

4 - 7

Valid until: Apr 22nd, 2012 9:00AM