Avalanche Forecast

Issued: Jan 11th, 2017 4:00PM

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

stephen holeczi, Parks Canada

Banff Yoho Kootenay.

We have a classic rockies snowpack, with a weak and faceted lower snowpack, and a mix of old and new wind slabs above. Conservative terrain choices will be your biggest defense against this tricky snowpack that will be here for the winter. SH

Summary

Weather Forecast

A continued NW flow in the alpine with increased winds Thursday afternoon.Â Temperatures will be in the -15 range at 2700-3000m with much colder temperatures(-20's)Â in the valley bottoms.Â No snow is in the forecast and we will have a gradual warmup into the weekend.Â

Snowpack Summary

Any of the new snow from the past few days has been blown to smithereens by northern winds at treeline and above. This has produced a reverse loading pattern, with hard slabs in many starting zone areas overlying a weak, faceted snowpack with numerous instabilities in the lower half of the snowpack. This is yesterdays snow profile from Bow Summit.

Avalanche Summary

A size 3 was reported yesterday on a SE aspect in the Sunshine backcountry which was likely triggered by reverse loading from North winds. Yesterday also saw some smaller skier triggered wind slabs that were cracking or running a short distance. No new avalanches were reported today.

Confidence

Due to the number of field observations on Wednesday

Problems

Wind Slabs

Winds from the north have created hard wind slabs in many areas, and these are reverse from normal locations. These slabs are hard to trigger, with a single person, but if they go it will be a dense piece of snow to ride.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Deep Persistent Slabs

The lower half of the snowpack is garbage, and will be for the distant future. Facets, crusts and depth hoar make for a very unsupported base for the snowpack. Large, avalanche prone features are out for now.

Be aware of the potential for wide propagations.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 3

Valid until: Jan 12th, 2017 4:00PM