Avalanche Forecast

Issued: Dec 25th, 2014 4:00PM

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.

Conrad Janzen, Parks Canada

Banff Yoho Kootenay.

The skiing has improved dramatically due to the recent snow, however there is a poor bond at the storm snow interface which will persist for some time. Avoid larger features, and steeper terrain. There is lots of good riding on low angled terrain.

Summary

Weather Forecast

Light snow flurries with sunny breaks, light W to NW winds, and temperatures between -5 and -15'C are forecast for the next several days.

Snowpack Summary

At tree line 10 - 30 cm of snow has fallen since Dec 23, with the heaviest snowfall occurring in Yoho Park. This new snow overlies the Dec 18 layer which consists of crust, facets and/or surface hoar depending on the location. A poor bond exists at this interface. At the base of the snowpack weak crusts and facets exist which are still a concern.

Avalanche Summary

Several avalanches up to Class 2.5 (with propagations up to 200 m) were observed running in the recent storm snow in Yoho Park on Dec 24th. Lake Louise ski hill also reported several natural and skier controlled avalanches up to size 2.5 within the past 48hrs, running in the new storm snow and occasionally stepping down to the basal facets/crusts.

Confidence

Due to the number of field observations

Problems

Storm Slabs

15 to 30cm's of recent storm snow is bonding poorly to previous surfaces and remains reactive to skier triggering.

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

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 storm snow avalanches may step down to this weak facetted layer.

Be aware of the potential for full depth avalanches due to deeply buried weak layers.Use careful route-finding and stick to moderate slope angles with low consequences

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 3

Valid until: Dec 26th, 2014 4:00PM