Avalanche Forecast

Issued: Dec 13th, 2014 4:00PM

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.

Conrad Janzen, Parks Canada

Banff Yoho Kootenay.

With blue skies in the forecast, it is important to remember that the base of our snowpack is still very weak. Stick to well supported, moderate angled terrain in the alpine. Ice climbers should also watch for the effects of solar heating above them.

Summary

Weather Forecast

A ridge of high pressure is building that will persist through Tuesday. Light winds, cooler temperatures and clear skies will be the norm for the next few days. Watch for some intense solar effect on steep south facing terrain.

Snowpack Summary

In the alpine a few cm`s of new snow overlies widespread wind slabs created by recent strong SW winds. At treeline and above, mild temperatures have helped strengthened the upper snowpack but the basal rain crust/facets remain weak. Below treeline a rain crust is present and the moist snow is gaining strength rapidly with the cooler temps.

Avalanche Summary

A few explosive triggered avalanches up to size 2 were observed at Sunshine Village today failing on the basal crust/facet combination. No new natural avalanches were observed today.

Confidence

Due to the number and quality of field observations

Problems

Deep Persistent Slabs

Natural avalanche activity has tapered off but snowpack tests show that the weak facets at the base of the snowpack continue to be a concern. With a stronger upper snowpack, triggering an avalanche is less likely but the consequences remain serious.

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

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Wind Slabs

Recent strong southwest winds have stripped windward areas and created fresh wind slabs in lee terrain in the alpine. If triggered these wind slabs can easily step down to the basal facets resulting in a larger avalanche than expected.

Use caution in lee areas. Recent wind loading have created wind slabs.Be careful with wind loaded pockets while approaching and climbing ice routes.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Dec 14th, 2014 4:00PM