Avalanche Forecast

Issued: Dec 6th, 2011 9:09AM

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

ccampbell, Avalanche Canada

Northwest Coastal.

Summary

Confidence

Fair - Timing of incoming weather is uncertain on Friday

Weather Forecast

Wednesday and Thursday: Mostly clear and dry, with freezing levels back to valley bottoms and moderate northwesterly winds. Friday: More snow is expected but the timing is uncertain. It could arrive as late as Friday evening. Freezing levels are expected to rise to 600m and winds shift to westerlies with the onset of precipitation.

Avalanche Summary

Numerous natural loose wet avalanches up to Size 2 with isolated Size 2.5s were observed during the warm and wet weather on Monday. Large glide avalanches from steep rock slabs were also observed; one was reported to be size 3.5.

Snowpack Summary

Overnight rain up to 1000m in the north, and alpine elevations in the south, likely melted surface hoar, settled surface facets, and froze into a crust. Glide cracks are opening and cornices are weakening.

Problems

Cornices

Recent warm temperatures weakened cornices and rapid cooling may stress them even more. A hazard in themselves, but also a large trigger for wind slabs on the slope below.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 3

Wind Slabs

Isolated weak wind slabs may still be lurking below ridge crests, behind terrain features, and in cross-loaded gullies.

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

2 - 4

Valid until: Dec 7th, 2011 8:00AM