Avalanche Forecast

Issued: Nov 20th, 2017 4:00PM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is low. Known problems include Storm Slabs, Loose Dry and Wind Slabs.

garth lemke, Parks Canada

Jasper.

Careful evaluation of the snowpack and new storm snow instabilities is required. Reports of skier triggered avalanches in the surrounding neighborhood is a reminder to be cautious and conservative.More snow may be coming!!

Summary

Weather Forecast

Tuesday will see 10cm of snow by the end of the day, light to moderate SW winds, and -8 degrees. The snowfall increases Wednesday to Thursday bringing maybe 60-80 cm of snow, strong winds, and warm temperatures. It may get really warm and snow allot!

Snowpack Summary

25cm of new snow with Strong Westerly winds occurred Sunday. This rests on a previous old snow surface windslab combination, the Oct 31 crust approximately 50cm down, and a spotty distributed Oct 17 crust just off the ground at lower to treeline elevations. The storm snow instability will linger for a few days and deserves your respect.

Avalanche Summary

Monday's patrol observed numerous fresh size 2's mainly at treeline but also a few noted in lower alpine locations. They ranged from 35-45 degrees, 100m wide, 20-40cm deep, running to top or mid track.

Confidence

Timing, track, or intensity of incoming weather system is uncertain

Problems

Storm Slabs

The recent 25cm of snow will be reactive for a few days until it has had time to settle. This problem was active on Monday. More snow starting on Tuesday extending into Thursday may add to this problem.

Use caution in alpine and open treeline lees. Recent snowfall has created storm slabs.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Loose Dry

The 25cm of new snow is enough to create loose avalanches in steep terrain or gullies. Extra heads up for ice climbers.

Avoid terrain traps, such as gullies, where the consequences of a small avalanche could be serious.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Wind Slabs

Sunday's storm had strong SW winds. Expect windslabs to have developed particularly on lee aspects.

Be careful with wind loaded pockets while approaching and climbing ice routes.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Nov 21st, 2017 4:00PM