Avalanche Forecast

Issued: Dec 28th, 2013 4:37PM

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

Grant Statham, Parks Canada

Banff Yoho Kootenay.

The only thing certain about the snowpack right now, is how unpredictable it is.

Summary

Weather Forecast

The NW flow continues to run down through the forecast region keeping temperatures cool with bursts of snowfall and gusty winds as systems embedded in this flow pass through the area. Trace amounts of snow are expected for Sunday; then another 5 cm for Monday.

Snowpack Summary

10-20 cm of soft surface snow has formed thin windslabs in some areas, and sits on top of a shallow and weak snowpack. West of the Continental Divide the snowpack is stronger, but failures near the ground are still likely. This condition will persist until the passage of time and deeper snow can work to strengthen the lower half of the snowpack.

Avalanche Summary

There is a pattern emerging in the Lake Louise area where the snowpack is the shallowest. Steep gullies in alpine areas are producing 100cm deep avalanches to ground (up to size 2), with triggering occurring from thin spots where the snowpack is weakest. A ride in these full-depth avalanches would cause serious injury getting raked over the rocks.

Confidence

Problems

Deep Persistent Slabs

This problem is classic. Hard to trigger, but when you hit the sweet spot (which you cannot see), full depth avalanches are likely. Don't ski aggressive terrain, the consequences are high so mange your exposure to starting zones very carefully.

Be aware of the potential for full depth avalanches due to deeply buried weak layers.Be aware of thin areas that may propogate to deeper instabilites.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 3

Wind Slabs

10-20 cm of light new snow has fallen in the last 48-hours, and has been blown into thin windslabs in some areas. Check for windslabs and avoid freshly loaded areas. Ice climbers should watch out in steep cliffy terrain.

Be careful with wind loaded pockets while approaching and climbing ice routes.Avoid freshly wind loaded features.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Dec 29th, 2013 4:00PM