Avalanche Forecast

Issued: Mar 6th, 2013 9:02AM

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

triley, Avalanche Canada

Cariboos.

The February 12th persistent weak layer continues to be a concern across the Interior Regions. Avalanches failing on this layer of buried surface hoar will be large and destructive.

Summary

Confidence

Fair - Timing or intensity of solar radiation is uncertain on Thursday

Weather Forecast

Overnight and Thursday: Mostly sunny with light Northwest winds and no precipitation. Freezing level rising to 1200 metres during the day. Alpine temperature -9.0 overnight.Friday: The ridge is expected to continue to influence most of the province bringing mostly sunny skies and light winds with freezing levels rising to about 1200 metres.Saturday: Becoming cloudy overnight with light precipitation and moderate Southwest winds.

Avalanche Summary

A few small avalanches up to size 1.0 were reported from Tuesday. Natural cornice fall continues to be a concern when the sun is shining.

Snowpack Summary

New sun crusts are reported to be forming on solar exposed aspects as the spring sun starts to pack more of a punch. The recent storm snow is settling, but storm slab releases are still possible. The weak layer of surface hoar that was buried around February 12th may be triggered by storm snow avalanches in motion, or by cornice fall and other large triggers. The strong solar radiation may trigger some cornice fall or release moist point releases in steep terrain that may step down to one of the deeper weak layers. I expect that the next couple of days will be a tricky combination of avoiding areas that slid during the warm wet weather, and gaining confidence in the areas that did not slide.

Problems

Persistent Slabs

There is a weak layer of surface hoar buried down about 100-150 cms (February 12th layer) that may continue to be triggered by large forces like cornice fall or storm snow avalanches in motion.

Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

4 - 7

Cornices

Recent cornice growth may not be well bonded and may fall off naturally during periods of strong solar radiation.

Pay attention to overhead hazards like cornices.>Stay well back from cornices.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 4

Storm Slabs

The recent storm snow continues to settle and bond, but may continue to be triggered by human activity. Strong solar radiation may cause increased activity on sun exposed aspects.

The new snow will require several days to settle and stabilize.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Valid until: Mar 7th, 2013 2:00PM