Avalanche Forecast

Issued: Feb 6th, 2016 4:00PM

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

snow safety, Parks Canada

Banff Yoho Kootenay.

Touchy windslabs are common in the alpine and at treeline. Avoid avalanche terrain for a while.

Summary

Weather Forecast

15 to 20 cm fell last night. winds over 100km/hr continue at the time of writing but are expected to begin to taper. there is an initial trend to cooler weather as the cold front finishes passing and then a few days of warm and dry weather. It is expected that the avalanche hazard will remain considerable for a while.

Snowpack Summary

Wind slabs are forming in the alpine and at tree line that are easy to trigger. The Jan 6 surface hoar/facet/sun crust layer, down 30-100cm, is becoming less reactive to skier triggering, however sudden collapse results persist on the Jan 6 and Dec 3 layers. Isolated whumphing on mid-pack facets/surface hoar have been observed this past week.

Avalanche Summary

Poor visibility has limited avalanche observations today. The Forecast avalanche cycle is expected to continue as the wind moves around to the NW and begins to calm tonight.

Confidence

Problems

Wind Slabs

New snow and very strong winds have created touchy wind slabs in the alpine.

If triggered the wind slabs may step down to deeper layers resulting in large avalanches.

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

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 3

Persistent Slabs

An average of 30-60 cm overlies the Jan 6 layer of surface hoar, facets and sun crust. Test results on this layer show it has become stubborn to trigger, but potential for wide propagation remains. The new snow will increase the likelihood of this.

Use careful route-finding and stick to moderate slope angles with low consequencesAvoid open slopes and convex rolls where buried surface hoar may be preserved.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

2 - 3

Valid until: Feb 7th, 2016 4:00PM