Avalanche Forecast

Issued: Feb 27th, 2017 4:00PM

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

garth lemke, Parks Canada

Jasper.

Cautious decisions are key particularly on large terrain features or those around terrain traps. Forecasters do not have much confidence in the snowpack as whumphing continues. Evaluate snow and terrain carefully.

Summary

Weather Forecast

Expect -12 to -18 degrees Celsius and light winds for Tuesday. Winds will pick up Westerly with a little bit of snowfall starting Tuesday night extending into Thursday. Temperatures will be warming slightly.Â

Snowpack Summary

A persistent slab at TL and ALP is buried by 5-10cm of snow and light winds making for powdery conditions. A rain crust is buried by this recent snow below 1900m. A somewhat dense upper snowpack overlies a weak faceted base making for unpredictably dangerous avalanche conditions. A surface hoar layer may be 40cm deep yet remains unconfirmed.

Avalanche Summary

No patrol on Sunday or Monday. Nothing new noted on Saturday. 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.

Confidence

The weather pattern is stable

Problems

Deep Persistent Slabs

Whumphing is occurring in un-skied terrain. It seems to be improving but suspect pockets of weakness just waiting for the trigger. Cold temperatures continue to promote facetting.

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

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 3

Persistent Slabs

Persistent slabs are buried under 5-10cm of new snow. It potentially overlies a buried surface hoar from Feb 10 but difficult to locate. Be vigilant particularly in sheltered spots where buried surface hoar may be lurking.

Use conservative route selection, choose moderate angled and supported terrain with low consequence.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Valid until: Feb 28th, 2017 4:00PM