Avalanche Forecast

Issued: Nov 25th, 2012 4:04PM

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

snow safety, Parks Canada

Banff Yoho Kootenay.

There is still a chance of triggering a large slide in the right terrain feature as wind loading and settling stiffen up the slab. Stick to moderate terrain and travel is good. JBW

Summary

Weather Forecast

Little in the way of precipitation for Monday. Skies become cloudy and then a chance of flurries and some moderate accumulations through midweek with a westerly flow. Artic front and some upslope by Thursday.

Snowpack Summary

Still very little wind effect in last weeks storm. Storm snow is approx. 40 cm. Stellar layer under Hst down approx 30-50 and Noc Cr down 60-80 are major layers. Relatively well settled snowpack for end of November.

Avalanche Summary

Avalanche control in Yoho on Bosworth and Stephen produced thin storm snow slabs up to size 2 none stepping down. Wind loading on NE face of Rundle produced a size three natural likely on Nov crust.

Confidence

Intensity of incoming weather systems is uncertain

Problems

Wind Slabs

20-40 cm thick soft and hard slabs, reactive to explosives and ski cuts and restricted mostly to immediate lee of ridge crests or in open areas Somewhat isolated and stubborn to trigger

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Persistent Slabs

The load on this layer is in the critical range. Open areas at treeline have just enough stiffness in the slab to have the potential for deep triggering and propagation. Several Na, skier and explosive avalanches up to size 2.5 in the last 36 hrs.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Nov 26th, 2012 4:00PM