Avalanche Forecast

Issued: Feb 24th, 2017 4:00PM

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

garth lemke, Parks Canada

Jasper.

Cautious decisions are key particularly on large terrain features or those around terrain traps. Consequences would be severe. Remotely triggered avalanches notes in our region today.

Summary

Weather Forecast

Flurries now to Tuesday with light westerly winds. Expect -10 to -20 degrees celsius with the coldest being Saturday.

Snowpack Summary

Windslabs exist at TL and ALP. A rain crust is below 1900m. A dense upper snowpack overlies a weak faceted base making for unpredictably dangerous avalanche conditions. Feb 10 SH layer may be 40cm deep yet its reactivity remains dormant.

Avalanche Summary

Friday's patrol observed 2 avalanches remotely triggered by skiers size 1.5-2 in Columbia Icefield area at 2000m treeline elevation. Two size 2-2.5 noted in the alpine south of Parkers ridge. One was a cross-loaded NW alpine feature, the other was triggered by cornice failure. Some loose dry activity size 1 noted in steep alpine terrain.

Confidence

The weather pattern is stable

Problems

Deep Persistent Slabs

Widespread whumphing and shooting cracks in previously un-skied terrain. Recent natural activity and remote triggering of this weakness resulted in avalanches up to size 3 failing on the weak faceted snowpack. Caution is recommended.

Watch for shooting cracks or stiffer feeling snow. Avoid areas that appear wind loaded.Be aware of thin areas that may propogate to deeper instabilites.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 3

Wind Slabs

Windslabs have developed and will persist as the weather remains static. Potentially overlying buried surface hoar from Feb 10 so be vigilant particularly in the alpine and open tree-line features.

Be aware of the potential for wide propagations due to the presence of hard windslabs.Use caution in lee areas. Recent wind loading have created wind slabs.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Valid until: Feb 25th, 2017 4:00PM