Avalanche Forecast

Issued: Nov 17th, 2012 4:00PM

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

chris gooliaff, Parks Canada

Banff Yoho Kootenay.

The strength of the SW flow seems to ebb by the time it arrives in our region. As a result, expect little change unless we receive a good pulse of moisture on Monday.

Summary

Weather Forecast

Forecast models indicate the main pulse of moisture may pass further to the south of our region. Expect unsettled weather Sunday with a pulse of snow (15-20cm) Monday. Freezing levels will drop to valley bottom, winds will be strong from the SW

Snowpack Summary

The new snow that may fall on Sunday/Monday will be accompanied by strong SW winds. This will likely create touchy soft/hard slabs at alpine and treeline elevations, especially in lee features. Pay attention to the amount of snow that is falling, as well the ridge-top winds above you.

Avalanche Summary

No natural activity reported today.

Confidence

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

Problems

Wind Slabs

With the strong winds and snow forecasted, new soft slabs will begin forming on Sunday in alpine and treeline locations. These new slabs will initially be touchy. Currently, slabs that are found in lee features have been stubborn to move.

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

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Persistent Slabs

Deep slabs size 2-3 have been noted on isolated steep alpine slopes over the past week. Failure plane was at the bottom of the snow pack on firn or glacier ice. No new have been reported these last few days but are still possible in the high alpine.

Be aware of the potential for full depth avalanches due to deeply buried weak layers.

Aspects: North, North East, East.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Nov 18th, 2012 4:00PM