Avalanche Forecast

Issued: Dec 14th, 2013 4:00PM

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

conrad janzen, Parks Canada

Banff Yoho Kootenay.

Increased wind loading due to light precipitation and moderate to strong W winds is the main thing to watch over the next several days. Ice climbers in particular should be aware of possible changing conditions high above them. CJ

Summary

Weather Forecast

Cloudy weather with light precipitation and moderate to strong W winds at ridge tops are forecast for the next several days.Â Temperatures should remain between -6Â and -14'C.Â 5-10cm of new snow is expected on Monday and Tuesday.

Snowpack Summary

10-20cm of recent storm snow sits on the early December facets. Strong W winds are creating wind slabs on lee aspects at tree line and in the alpine. The mid pack is mainly facets but still dense enough to support the weight of a skier in many areas. In alpine areas the October melt freeze crust is present near the base of the snow pack.

Avalanche Summary

A couple of wind triggered natural avalanches up to size 2 have been reported out of lee aspects on steep alpine terrain in the last 48hrs with one close call reported on Polar Circus on Cirrus Mountain. With the mild temperatures cornices are forming and are quite delicate at this time.

Confidence

Intensity of incoming weather systems is uncertain

Problems

Wind Slabs

New snow and strong W winds are creating wind slabs in lee areas. Not much activity has been observed yet however the hazard is slowly increasing and these wind slabs have the potential to step down into the basal facets to create larger avalanches.

Be cautious as you transition into wind affected terrain.Minimize overhead exposure; avalanches triggered by wind loading may travel long distances.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Deep Persistent Slabs

The base of the snowpack is still quite weak with the Oct melt freeze crust and basal facets still providing good sliding layers under the right conditions. Probe often for basal weaknesses and use caution in steeper terrain.

Be aware of the potential for full depth avalanches due to weak layers at the base of the snowpack.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Dec 15th, 2013 4:00PM