Avalanche Forecast

Issued: Feb 4th, 2013 9:31AM

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

jlammers, Avalanche Canada

Kootenay Boundary.

Summary

Confidence

Fair - Intensity of incoming weather is uncertain

Weather Forecast

Tuesday: Light snowfall / Strong southwest winds / Alpine temperature of about -7.0Wednesday: Moderate snowfall / Strong to extreme west winds / Alpine temperature of about -9.0 Thursday: Light amounts of new snow in the morning with clearing in the afternoon / Light west winds / Alpine temperature of about -7.0

Avalanche Summary

A few size 1 slabs have recently been reported running on the January 23rd interface. They ran 30cm deep between 1800m and 1900m on east facing terrain. With forecast weather, I would suspect a spike in new snow instabilities. With the increased load on the January 23rd interface, persistent slab avalanches are likely to increase in size and destructive potential.

Snowpack Summary

Light amounts of new snow overlie hard and soft wind slabs in exposed areas, surface hoar on a variety of aspects and elevations, and a crust on previously sun-exposed slopes. About 30-40cm below the surface, an interface of surface hoar, facets or sun crust buried on Jan 23 seems to be gaining strength in some areas. Having said that, skier-triggered avalanches are still occurring, and I would continue to be cautious about this weakness as the overlying slab continues to develop over the next few days.The snowpack below this is generally well bonded.

Problems

Wind Slabs

Forecast strong southwest winds and light snowfall will create fresh and reactive windslabs in lee terrain.

Be cautious as you transition into wind affected terrain.>Avoid freshly wind loaded features.>

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Persistent Slabs

A mixed bag of weak interfaces is buried about 40 cm down. The nature of these weaknesses varies considerably from slope to slope.

Make observations and assess conditions continually as you travel.>Choose well supported terrain without convexities.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 4

Valid until: Feb 5th, 2013 2:00PM