Avalanche Forecast

Issued: Feb 28th, 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 Persistent Slabs.

garth lemke, Parks Canada

Jasper.

Winds are going to increase starting Wednesday morning. There is snow available to transport increasing the probability of overloading an already weak snowpack. Even more snow and stronger winds forecast for Friday.

Summary

Weather Forecast

In the Columbia Icefields, expectÂ for Wednesday -10 to -16 degrees Celsius, flurries, and 25km/hr Westerly winds. Thursday and Friday winds will pick up Westerly 50km/hr Alpine and Treeline, trending warmer temperatures, and 15-25cm of snow Thursday night into Saturday. Still a few days away but one can hope and offer sacrifices to Ullr.

Snowpack Summary

A persistent slab at TL and ALP is buried by 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

Tuesday's patrol up Cavel road observed no new natural activity but this is only a small part of our region. Snowpack was extremely weak underfoot.Â

Confidence

Wind effect is extremely variable

Problems

Deep Persistent Slabs

Whumphing is occurring in un-skied terrain. Suspect pockets of weakness just waiting for the trigger particularly shallow spots. Cold temperatures continue to promote facetting weakening an already weak mid pack and base.

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

Persistent Slabs

Persistent slabs are buried under 10cm of snow. It potentially overlies a buried surface hoar from Feb 10 but it's 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: Mar 1st, 2017 4:00PM