Avalanche Forecast

Issued: Feb 20th, 2016 4:29PM

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

stephen holeczi, Parks Canada

Banff Yoho Kootenay.

We are still getting daily reports of close calls and avalanche observations in this region. It's not the time to step into bigger terrain given the current snowpack, and will take some time to gain confidence. SH

Summary

Weather Forecast

Sunday looks slightly cooler with valley bottom freezing levels, and some sun in the Eastern portions. Winds will mainly be light Westerly, picking up later in the day with the chance of some light snow overnight into Monday.

Snowpack Summary

Fresh windslabs and cornice growth in the alpine with 30 to 50 cm since the warming a week ago. A 50-100 cm slab overlies the January 6th weak layer of surface hoar, facets and sun crust and snowpack tests indicate an unstable bond between the two. The lower snowpack is facetted and quite weak in thinner areas but is more settled in thicker areas.

Avalanche Summary

Snowshoers remote triggered a size 1.5 while approaching the climb Bow Falls today. This was at an upper treeline elevation. Another size 2.5 skier triggered avalanche occurred in the alpine area of Vermillion Peak in Kootenay, scrubbing to ground. Other natural activity to size 2.5 noted on a flight this afternoon occurring in the last 24 hours.

Confidence

Due to the number of field observations on Saturday

Problems

Persistent Slabs

50-100 cm of snow overlies the Jan 6th layer of surface hoar, facets and sun crust. Numerous reports of avalanches triggered on this layer over the last 24 hours show that it is active. In thinner areas, isolated avalanches have scrubbed to ground.

Use conservative route selection, choose moderate angled and supported terrain with low consequence.Avoid paths that have not avalanched recently.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

2 - 3

Wind Slabs

Be mindful of cross loaded features and the lees of ridges where moderate to strong W winds have recently formed windslabs 10-40+ cm thick. If triggered, there is potential to step down to the persistent weak layer and to ground in thin areas.

Use caution in lee areas. Recent wind loading has created wind slabs.If triggered the wind slabs may step down to deeper layers resulting in large avalanches.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Valid until: Feb 21st, 2016 4:00PM