Avalanche Forecast

Issued: Mar 5th, 2013 4:00PM

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

garth lemke, Parks Canada

Jasper.

Expect potential for human triggering and natural avalanches to increase with afternoon sun particularly S aspects. Ice climbers need to start and end early to avoid the increased danger in the afternoon.

Summary

Weather Forecast

The next few days will be cold during the night, perhaps some overnight flurries, followed by sunny conditions and freezing levels rising to 1800m or higher in the afternoon with the suns energy on steep solar aspects and South facing bowls or gullies.

Snowpack Summary

A significant amount of snow arrived last weekend with warm temperatures and light winds creating a soft slab and storm snow instability on all aspects and elevations. The snow sits on previous windslab surfaces at treeline and above and on a faceted snowpack at lower elevations. Winds have yet to slab up the new snow. Monitor for that condition.

Avalanche Summary

Monday's explosive control work produced some size 3 soft slabs in the Icefields and Maligne lake alpine areas. They slid on the storm snow interface. A few dusted the highway. Natural activity was limited but a few size 2-3's were noted. Winds still need to slab up the storm snow. Gullies above polar circus were 85% cleaned out with control work.Â

Confidence

Timing or intensity of solar radiation is uncertain

Problems

Loose Dry

As the sun peaks out and warms up the day, loose avalanches with significant mass are occurring with increased frequency. They are initiating out of steep W or S facing high elevation rocks or gullies.

Finish ice climbs early in the day before the temperature rises.he snowpack will deteriorate in the afternoon.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 3

Storm Slabs

The storm slabs remain soft in nature as winds have yet to firm them up. Soft slab conditions do exist on gully sidewalls and some large alpine slopes as Monday's explosive control work demonstrated. Watch for wind building slabs with this snow.

Sluffs may trigger deeper instabilities.Avoid freshly wind loaded features.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Mar 6th, 2013 4:00PM