Avalanche Forecast

Issued: Dec 28th, 2014 4:00PM

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

Conrad Janzen, Parks Canada

Banff Yoho Kootenay.

We are in a holding pattern and have little confidence in our snowpack at tree line and above. Continue to avoid steep or convex terrain especially if there are terrain traps below, and enjoy the good skiing on lower angled well supported slopes.

Summary

Weather Forecast

Cloudy overnight then clearing skies with cold temperatures and NE winds are forecast for Monday. A warming trend with continued clear skies is forecast for Tuesday and Wednesday.

Snowpack Summary

Recent winds have created small wind slabs in the alpine which sit over the Dec 18 layer 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 also a concern. Overall the snowpack is quite weak and does not inspire much confidence.

Avalanche Summary

A skier triggered size 1.5-2 avalanche was reported today in the Wizard Chutes near Healy Creek at approximately 1900m. It started as a small wind slab near tree line and then stepped down to the basal facets. Other small skier and explosive triggered wind slabs have been reported by the local ski areas in the last 48hrs.

Confidence

Problems

Persistent Slabs

10 to 25cm's of snow from last week is bonding poorly to previous surfaces and remains reactive to skier triggering in areas where there is some wind loading and slab development. This is more of a problem in the western areas of the park

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

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Deep Persistent Slabs

A weak and facetted basal layer exists at the bottom of the snowpack. It is still possible to trigger this in many areas at tree line and above. Areas with more wind loading or a stiffer slab above the weak basal facets are of the greatest concern.

Use careful route-finding and stick to moderate slope angles with low consequencesBe 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

Valid until: Dec 29th, 2014 4:00PM