Avalanche Forecast

Issued: Feb 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.

garth lemke, Parks Canada

Jasper.

Despite the sun, the air temperature remains cool. Caution advised when sun is baking slopes above as this will incrementally increase the danger rating.

Summary

Weather Forecast

Thursday will have variable cloud, seasonal temperatures, light flurries, and light to gusting moderate SW ridgetop winds. Friday will have flurries, SW winds possibly blowing extreme at 3000m and brisk at treeline ridgetops. The snow is not expected to arrive until Friday evening with 15-20cm (11mm water equivalency) by Saturday a.m..

Snowpack Summary

Variable windslabs exist in the alpine and exposed treeline locations. Overall they are bonding well to the previous surfaces. Many spots have been stripped of Saturday's storm snow revealing previous sastrugi and windslab surfaces with windpressed pockets in between. Its looking like it was a week ago. Weak facets dominate low elevations.Â

Avalanche Summary

No Wednesday patrol. Tuesday's patrol observed only a couple size 1.5 very steep loose avalanches @ 2600m appearing to be solar triggered. One size 2 thin slab was noted at 2700m E aspect on a very steep unsupported feature. They appear to be stopping where angle changes.Â No naturals were noted on Monday and visibility was good.

Confidence

The weather pattern is stable on Thursday

Problems

Wind Slabs

Saturday's 20cm of snow has evolved into windslab that appears to be bonding well. These slabs sit on a variety of surfaces such as previously hard slab and sastrugi.

Assess start zones carefully and use safe travel techniques.Caution in lee and cross-loaded terrain near ridge crests.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

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