Avalanche Forecast

Issued: Dec 24th, 2014 4:29PM

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

brian webster, Parks Canada

Banff Yoho Kootenay.

Recent snow has improved the skiing dramatically, however there is a poor bond at the storm snow interface. Avoid larger features, and steeper terrain. There is lots of good riding on low angled terrain.

Summary

Weather Forecast

Christmas day will be cloudy with isolated flurries and an alpine temperature high of minus nine. Friday's forecast is for mixed sun and cloud, and light winds. Only flurries forecasted for the weekend.

Snowpack Summary

At treeline between 10 and 30 cm of snow has fallen since Tues, with the heaviest snowfall occurring in Yoho Park. The new snow overlays the Dec 18 layer which consists of crust, facets and/or surface hoar depending on location. A poor bond exists on this storm snow interface.

Avalanche Summary

In Yoho backcountry several avalanches up to Class 2.5 (with propagations up to 200 m) were observed running in recent storm snow. Lake Louise ski hill reported several natural and skier controlled avalanches running in the storm snow.

Confidence

Problems

Storm Slabs

Twenty to forty cms of recent storm snow is bonding poorly to previous surfaces and is reactive to skier triggering.

The new snow will require several days to settle and stabilize.Watch for whumpfing, hollow sounds, and shooting cracks.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Deep Persistent Slabs

A weak and facetted basal layer exists at the bottom of the snowpack. Smaller avalanches may step down to this weak facetted layer.

Be aware of the potential for full depth avalanches due to deeply buried weak layers.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 3

Valid until: Dec 25th, 2014 4:00PM