Avalanche Forecast

Issued: Jan 10th, 2015 4:13PM

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

conrad janzen, Parks Canada

Banff Yoho Kootenay.

The weak snow pack does not give us much confidence in steep terrain or large features especially at tree line and above where more of a surface slab exists. Stick to moderate angled, well supported terrain, and enjoy the recent snow fall!

Summary

Weather Forecast

Moderate alpine temperatures between -5 and -10'C with light winds out of the NW and a mix of sun and cloud are expected for the next several days.

Snowpack Summary

Wind slabs are present in many open areas above tree line. Below this the snow pack is quite weak and facetted in most places. The Dec 18 crust/facet interface is down 30-40cm at tree line and we are still getting lots of whumphing on this layer. The bottom half of the snow pack consists mostly of facets.

Avalanche Summary

Natural avalanche activity has tapered off but human triggering remains likely. A size 1.5 skier triggered avalanche occurred in the Wizard Chutes near tree line Jan 10th in the Sunshine area. Avalanche control at Lake Louise on Jan 9th resulted in a size 3 which initiated on the Dec 18th interface and then stepped down to facets near the ground.

Confidence

Problems

Persistent Slabs

We are getting lots of large whumphs on the Dec 18th layer consisting of facets/crust. This indicates the potential for skier triggering in steep terrain. Areas where the snow over this layer has stiffened into more of a slab are of the most concern.

Be aware of thin areas that may propogate to deeper instabilites.Caution in lee and cross-loaded terrain near ridge crests.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 3

Deep Persistent Slabs

In many areas of the forecast region the potential for avalanches to step down to the basal facets is still possible. Large propagations are also possible and the resulting avalanche could be quite destructive.

Use conservative route selection, choose moderate angled and supported terrain with low consequence.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 3

Valid until: Jan 11th, 2015 4:00PM