Avalanche Forecast

Issued: Jan 2nd, 2012 10:37AM

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

jfloyer, Avalanche Canada

Cariboos.

Summary

Confidence

Fair - Intensity of incoming weather is uncertain

Weather Forecast

Tuesday: up to 20 cm new snow with freezing levels around 1600 m. Strong southwesterly ridgetop winds. Wednesday: 10 cm new snow or rain with freezing levels rising to 2000 m. Strong Southerly ridgetop winds. Thursday: 5 cm new snow, freezing levels lowering to around 1000 m.

Avalanche Summary

Two large (size 3) cornice-triggered avalanches occurred in the alpine on Sunday. One stepped down into lower facet layers producing a crown up to 2 m deep. Another cornice-triggered avalanche occurred on Monday on a north aspect in the alpine; this one did not pull out a slab on the slope below.

Snowpack Summary

100 - 150cm of total storm snow has fallen in the region since Christmas. Winds have redistributed the storm snow into wind slabs that are quite widespread; you can find them at and above treeline in wind exposed locations. Even open areas below treeline are suspect for wind affected snow. A surface hoar/facet/crust interface (persistent weakness aka PWL) from mid-December is buried anywhere from 100-150cm deep & has been quite reactive making for touchy avalanche conditions.

Problems

Wind Slabs

Big winds combined with plenty of snow available for transportation have resulted in widespread wind slabs on lee slopes. I'd be suspect of any open slope, even around treeeline.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 5

Persistent Slabs

Surface hoar buried about a meter below the surface has created a dangerous and tricky avalanche problem. Activity has slowed in the Caribou's, but this layer needs to be treated with great caution. Conservative terrain choices are appropriate.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

3 - 7

Cornices

Warm alpine temperatures have made cornices unstable.

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

Elevations: Alpine.

Likelihood

Likely

Expected Size

3 - 6

Valid until: Jan 3rd, 2012 8:00AM