Avalanche Forecast

Issued: Nov 26th, 2017 4:00PM

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

deryl kelly, Parks Canada

Jasper.

Icefields Parkway is closed from Saskatchewan Crossing to Athabasca Falls due to planned avalanche control. Check Alberta 511 for updated opening time.

Summary

Weather Forecast

15cm of storm snow with a further 15 to 20 cm forecasted overnight for Sunday. Snow to continue through until Tuesday afternoon. Cool alpine Temperatures up to -5. Strong to Moderate SW winds with gusty extreme winds to accompany this the remainder of the storm cycle.

Snowpack Summary

30cm of recent storm snow over a 10cm hard crust with more coming. A persistent slab between 40cm - 150cm thick sits on the Halloween Crust, low in the snowpack. This crust can be found up to 2,700m depending on its location. Wind and storm slabs likely exist in the upper alpine.

Avalanche Summary

Field team on Sunday monitoring growing storm slab over the Black Friday crust down 35cms. No new avalanches observed on the crust but visibility poor above TL. On Nov. 22nd a field team remote triggered 3 simultaneous size 2 persistent slabs 60-150m away on either side of the wind scoop at parkers ridge.

Confidence

Problems

Storm Slabs

Building slabs over the Black Friday (Nov. 23rd) crust will continue to grow overnight and become more sensitive to light triggering by Monday morning. Extremely cautious travel is advised until the hazard subsides.

Avoid avalanche terrain during periods of heavy loading from new snow and wind.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Wind Slabs

Sensitive wind slabs building quickly at ridge tops and if triggered, has the potential to step down to the deeper instability.

Avoid freshly wind loaded features.Avoid avalanche terrain during periods of heavy loading from new snow and wind.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Persistent Slabs

This is a complex problem which is hard to assess and predict. Give yourself a wide margin and make conservative terrain choices.

Be aware of the potential for wide propagations.Be wary of slopes that did not previously avalanche.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 3

Valid until: Nov 27th, 2017 4:00PM