Avalanche Forecast

Issued: Mar 23rd, 2013 3:00PM

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

jeremy.mackenzie, Alberta Parks

Kananaskis.

Wind slabs remain sensitive to human triggering in steep terrain. Solar radiation will be a significant factor over the next few days. Pay attention to increasing danger levels as daytime heating and radiation affect solar aspects and cornices.

Summary

Confidence

Good - Timing or intensity of solar radiation is uncertain

Weather Forecast

Mostly sunny for the next several days with generally light winds. Temperatures will be seasonal and no precipitation is expected.

Avalanche Summary

A few naturally triggered slab and loose avalanches occurred today. A few small cornice failures also occurred. One significant slide, size 2.0, was observed midday on an East aspect at 2700m. This slide initiated as a small sluff, which then triggered several small slabs on the moderate angled rock bands below. Debris was channeled into a gully feature.

Snowpack Summary

The snowpack continues to settle. Moist snow on steep solar aspects in the afternoon. Wind slabs remain prominent in Alpine and open Treeline terrain, especially on N and E aspects. These slabs are sensitive to human triggering in steep, convex or un-supported terrain. Cornices are large in some areas and regular failures have been occurring over the past several days. Buried crust layers are a concern on solar aspects when radiation is high and/or temperatures are warm.

Problems

Wind Slabs

A variety of wind slabs have been created over the last week. These slabs are now hidden under 15 to 20cm of recent snow, but remain sensitive to human triggering in steeper terrain.

Choose well supported terrain without convexities.>Avoid lee and cross-loaded terrain near ridge crests.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 5

Persistent Slabs

A few crust layers are found in the upper snowpack. These crusts reach as high as 3000m on S aspects and 2200m on other aspects. Monitor the location of these layers within the snowpack and assess the bond with layers above.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>Be aware of thin areas that may propagate to deeper instabilites.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 5

Cornices

Cornice failures continue to be a theme, with several failures triggering slab avalanches in recent days. Be aware of overhead exposure especially during times of intense solar radiation.

Pay attention to overhead hazards like cornices.>Stay well to the windward side of corniced ridges.>

Aspects: North, North East, East.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 5

Valid until: Mar 24th, 2013 2:00PM