Avalanche Forecast

Issued: Dec 7th, 2012 9:14AM

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

triley, Avalanche Canada

South Coast.

Summary

Confidence

Fair - Due to variable snowpack conditions on Saturday

Weather Forecast

Overnight and Saturday: A ridge of High pressure will build over the North Coast tonight and then move down onto the South Coast during the morning. Light snow is expected to bring a couple of cms to the region during the evening. Moderate Northwesterly winds and cooling temperatures (-12.0 in the alpine) are forecast by morning. Broken skies in the morning, with some sunny periods in the afternoon.Sunday: A warm front is expected to sweep across the coast on Sunday. Expect light to moderate westerly winds combined with moderate precipitation in the West of the region. Further inland only light precipitation is expected. Freezing levels should gradually rise up to about 1200 metres.Monday: Light precipitation and moderate westerly winds combined with freezing levels rising during the day to about 1300 metres.

Avalanche Summary

Explosive control in the Duffey Lake area resulted in avalanches up to size 2.5 that were 30-40 cms deep on Wednesday.

Snowpack Summary

The Coquihalla has a well settled "right side up" snowpack that is about 190 cms deep at 1550 metres elevation. "Right side up" means that the surface layers are light and soft, and then the layers get progressively more dense as you move down through the snowpack. The ski penetration has been reported to be about 40 cms and the foot penetration is very deep at 80 cms. The light snow is causing a lot of sluffing in steeper terrain, but is not reacting as a slab. The November crust has not been found in the Coquihalla, although we don't have any reports from the high alpine. Conditions may be quite different in the North of this region, please email us your observations if you are out in the field. forecaster@avalanche.ca

Problems

Wind Slabs

The recent storm has developed wind slabs in the alpine and at treeline that may be covered by 20-30 cms of new snow.

Stay off recent wind loaded areas until the slope has had a chance to stabilize.>Travel on ridgetops to avoid wind slabs on slopes below.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 4

Deep Persistent Slabs

An old facet/crust combination deep in the snowpack may wake up with heavy triggers, smaller avalanches stepping down, or triggering from thin-spots, particularly on slopes with smooth ground cover.

Be aware of the potential for full depth avalanches due to deeply buried weak layers.>

Aspects: North, North East, East.

Elevations: Alpine.

Likelihood

Unlikely

Expected Size

3 - 7

Valid until: Dec 8th, 2012 2:00PM