Avalanche Forecast

Issued: Feb 16th, 2016 4:01PM

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.

ian jackson, Parks Canada

Banff Yoho Kootenay.

We continue to see avalanche activity and close calls daily. It is NOT A GOOD TIME for big terrain. Stick to conservative terrain and enjoy the new snow!

Summary

Weather Forecast

The jet stream is over us so expect to get regular snow throughout the week. The next storm will come in on Wed PM and we should see continuous light snow accumulating to 10-15 cms by Friday PM. Freezing levels are warming to 1500m on Wed and spiking to 2000m on Thursday before lowering on Friday. Alpine winds will be moderate to strong W/SW.

Snowpack Summary

Fresh windslabs and cornice growth in the alpine with 15 to 30 cm of recent snow and west winds. 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 (<1.5m) and settled in thicker areas.

Avalanche Summary

Avalanche activity subsided Tuesday with minimal new snow overnight, however we are just coming out of a natural cycle on Sunday night and we have had many close calls in the last week. A new report yesterday of a size 2 low down on the approach to Bow hut that crossed the regular uptrack is indicative of activity we have been seeing lately.

Confidence

Freezing levels are uncertain on Thursday

Problems

Persistent Slabs

50-100 cms 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 5 days show that it is active. In thinner areas, isolated avalanches have scrubbed to ground.

Avoid paths that have not avalanched recently.Avoid areas with overhead hazard.

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 formed fresh 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.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Feb 17th, 2016 4:00PM