Avalanche Forecast

Issued: Feb 1st, 2012 9:54AM

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

triley, Avalanche Canada

Kootenay Boundary.

Summary

Confidence

Fair - Freezing levels are uncertain on Friday

Weather Forecast

A ridge of high pressure moving in from the coast is expected to produce light southerly winds combined with broken skies and freezing levels rising to about 1300 metres by Thursday afternoon. Warm temperatures are forecast to persist through the night and into Friday morning. More clearing is expected on Friday. Freezing levels are expected to rise to about 1500 metres, and solar radiation should be strong on sun exposed slopes. Alpine temperatures are forecast to be around -3.0 in the alpine. Saturday is expected to be mostly clear with temperatures a few degrees cooler than Friday.

Avalanche Summary

Report of a natural avalanche size 1.5 dry slab with a 20-30 cm crown at 1900 metres on Grey Mtn near Rossland. Skier accidental size 2.0 dry slab avalanche reported from the back country near Whitewater ski resort on a North aspect near treeline.

Snowpack Summary

The recent storm snow layer is about 30-50 cm thick and is quite variable across the region. There are a couple of thin crusts buried below the storm snow that have been producing moderate to hard shears in tests. Some areas are still getting sudden planar shears on the mid-december surface hoar layer. The forecast warming trend may weaken the bond on the mid-december layer; particular concern in low snowpack areas.

Problems

Wind Slabs

Recent windslabs are becoming more stubborn to trigger. Warm temperatures forecast should continue to settle and bond these instabilities.

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 4

Storm Slabs

Recent snowfall has added to the current storm slab problem. Watch for storm slabs on steeper, unsupported features.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 4

Cornices

Recent wind and snowfall has created sensitive new cornices at ridgetops. Cornice falls are a large load that may trigger deeply buried weak layers and cause large avalanches on the slopes below.

Aspects: North, North East, East.

Elevations: Alpine.

Likelihood

Likely

Expected Size

1 - 5

Valid until: Feb 2nd, 2012 8:00AM