Avalanche Forecast

Issued: Jan 28th, 2012 8:50AM

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

pgoddard, Avalanche Canada

Cariboos.

Summary

Confidence

Fair - Intensity of incoming weather is uncertain

Weather Forecast

Saturday night: 10-25cm further snow, with the freezing level near 1200m. Strong winds. Sunday: 10-25cm snow. Strong to gale westerly winds. Freezing level around 1200m.Monday: Light snow. Light to moderate westerly winds.Tuesday: A few flurries, with sunny breaks. Gusty westerly winds.

Avalanche Summary

Natural avalanches were observed below 1500m on Friday, failing on the crust/facet combo. On Thursday, a skier remotely triggered a size 1.5 slab on a convex feature. It failed on facets beneath the storm snow. On Wednesday, three size 3.5 natural avalanches ran full path. A few other natural avalanches, up to size 2, were observed in steep lee (wind-loaded) terrain. I expect more avalanche activity to occur during the weekend's storm.

Snowpack Summary

Up to 1m of snow has fallen since Monday. Strong winds have created hard slabs, soft slabs and fragile cornices. Key concerns as further snow builds this weekend include a weak facet layer that was created during the brutal cold snap in mid-January and a buried crust, with associated facets, which is found below about 1500m and is quite touchy in some areas. Snowpack test results on this layer range from no result to easy, sudden shears.

Problems

Wind Slabs

Wind slabs continue to build behind ridges and terrain breaks. Areas that avalanched earlier this week may re-load as the storm continues.

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

Elevations: Alpine, Treeline.

Likelihood

Very Likely

Expected Size

2 - 7

Storm Slabs

Storm slabs have been failing on buried weak layers at all elevations. Slabs will grow in size and may become more touchy with warming and snowfall this weekend.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

2 - 5

Cornices

Large cornices are looming over many slopes. A falling chunk could trigger an avalanche on the slope below.

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

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

3 - 5

Valid until: Jan 29th, 2012 8:00AM