Avalanche Forecast

Issued: Mar 5th, 2014 4:46PM

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

brian webster, Parks Canada

Banff Yoho Kootenay.

With the recent new snow and high uncertainty with the deeper layers now is the time for conservative decision making.

Summary

Weather Forecast

The storm will continue through to Thursday evening with another 15 cm forecasted. High temperatures in the alpine around -3 with light winds. Mixed sun and cloud with some flurries on Friday.

Snowpack Summary

Sunshine, Kootenay and Yoho areas have received thirty to 40 cm of storm snow since March 2. Lesser amounts around Lake Louise and Bow Summit. Forty to 80 cm of settled snow on the Feb 10 interface is producing moderate sudden planar results. Fresh windslabs up to 40 cm deep in alpine are reactive to skier control.

Avalanche Summary

Numerous skier controlled winds-slabs 40-60 cm deep up to size 2 reported from Sunshine. Two significant skier triggered avalanches (Class 2 and 2.5) reported at 1700 m (east aspect) in Kootenay. These initiated 50-100 cm down on the Feb 10 interface and propagated up to 100 m. This suggests that the Feb 10 layer may be getting overloaded.

Confidence

Forecast snowfall amounts are uncertain on Thursday

Problems

Wind Slabs

Lots of fresh snow and moderate southerly winds have created touchy wind slabs 40-60 cm deep in the alpine.

Be cautious as you transition into wind affected terrain.The new snow will require several days to settle and stabilize.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Persistent Slabs

Test results on the Feb 10 layer generally in the moderate range but still show lots of potential for good propagation if triggered. Recent storm snow may be enough to activate this layer (see avalanche details). Lots of uncertainly with this layer

Dig down to find and test weak layers before committing to a line.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Mar 6th, 2014 4:00PM