Avalanche Forecast

Issued: Jan 24th, 2015 7:05AM

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

matt.mueller, Alberta Parks

Kananaskis.

Steep south aspects had moist snow today. With temps on the rise, expect south aspects to be tricky skiing. If good turns are on order, staying low and looking for sheltered areas will be your best bet.

Summary

Confidence

Good

Weather Forecast

The big story is going to be the winds. They are expected to pick up tonight and peak tomorrow morning. 3000m winds will hit 155km/hr!! 2500m will be less at only 80km/hr! Looks like snow for Winnipeg. Other than the ridiculous winds, they day will be quite nice. Above zero at all elevations, and mostly clear skies.

Avalanche Summary

Forecasters witnessed one slab avalanche today that was triggered by sluffing in steep, unsupported cliff terrain. The avalanche eventually included all the trouble layers, including pulling out pockets on the Nov 6th crust. It was a size 2, NW asp, 40 degree plus terrain. Mt Buller was the area.

Snowpack Summary

A very windy day today. Even valley bottom saw some snow transport. The alpine is currently being raked by extreme winds. Cornices, sluffing and windslabs can all be expected from this wind event. The transition to alpine terrain was very distinct in terms of windloading. Open areas at treeline were instantly "slabby". These slabs extended well below ridgelines. On south aspects, various problem layers are becoming difficult to inspect/locate within the treeline snowpack. Generally it felt reasonably well settled with a weak base. No surprises. On other aspects, the snowpack is more obvious. The Dec crust is down 20-40 depending on wind orientation. Below treeline, the winds have had a slight effect on the snow surface but no real avalanche problems are there yet. Valley bottom snow depth is 70cm's, treeline is 90-100cm's and alpine is variable.

Problems

Wind Slabs

We have a series of windslabs that are generally well bonded to each other, but they are sitting on the Jan 16th surface hoar. To keep it tricky, the surface hoar layer appears to be spotty and hard to find. Assume it is there and dig to find/assess.

Dig down to find and test weak layers before committing to a line.>Avoid freshly wind loaded features.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Persistent Slabs

Upper treeline is where this is more of a concern. Steep, unsupported terrain is suspicious at the moment.

Avoid steep lee and cross-loaded features>

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 3

Deep Persistent Slabs

This is still on our radar. Especially with today's avalanche observation. Probing will give a good indication of this layer's location and quality.

Avoid shallow snowpack areas where triggering is more likely.>Avoid convexities or areas with a thin or variable snowpack.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 4

Valid until: Jan 25th, 2015 2:00PM