Avalanche Forecast

Issued: Mar 19th, 2013 3:00PM

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

jeremy.mackenzie, Alberta Parks

Kananaskis.

Light snow on Wed will do little to change the danger rating, but 10 to 15cm of snow on Wed night with strong SW winds will push the avalanche hazard up. Natural avalanche activity continues. Check Facebook for a couple of photos.

Summary

Confidence

Fair - Timing, track, or intensity of incoming weather is uncertain

Weather Forecast

Light flurries expected Wednesday with rising freezing levels and strong to extreme SW winds. A more vigorous precipitation event is possible Wednesday night.

Avalanche Summary

An isolated natural avalanche cycle continues, including cornice triggered slides. Observations today observed a few large avalanches in the alpine, primarily on solar aspects. Many of these slides have been running fairly far, and avalanches in shallow snowpack regions have stepped down to ground.

Snowpack Summary

3 to 5cm of new snow overnight. Moist snow on solar asp in the afternoon. Previous storm snow is settling rapidly. Storm slabs exist on all aspects in the alpine and open areas at treeline. Cornices have grown significantly. Several layers of crust exist in the upper snowpack, especially on solar aspects. These remain layers of concern during periods of warming and/or solar radiation.

Problems

Storm Slabs

Storm slabs averaging 40cm thick are present on all aspects in the Alpine and open areas at Treeline. In some cases the slabs sit on a crust layer. These slabs have produced a few recent large avalanches and are still sensitive to human triggering.

Avoid freshly wind loaded features.>Choose well supported terrain without convexities.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 5

Cornices

Significant cornice growth has occurred recently and several cornice failures have occurred in the past couple of days. These cornice failures are triggering avalanches on the underlying slopes.

Pay attention to overhead hazards like cornices.>Avoid exposure to overhead avalanche terrain, as large avalanches may reach the end of runout zones.>

Aspects: North, North East, East.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 4

Persistent Slabs

Several crust layers are found in the upper snowpack. These crusts reach as high as 3000m on S aspects and between 22-2400m on other aspects. Carefully evaluate the bond at these interfaces and be cautious during times of solar radiation.

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

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 4

Valid until: Mar 20th, 2013 2:00PM