Avalanche Forecast

Issued: Jan 28th, 2012 9:29AM

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

jlammers, Avalanche Canada

Sea To Sky.

Summary

Confidence

Fair - Intensity of incoming weather is uncertain on Sunday

Weather Forecast

Sunday: moderate to heavy snowfall / strong southwest winds decreasing in the afternoon / freezing levels reaching 1300m Monday: light snowfall / moderate southwest winds / freezing level at 800m Tuesday: light snowfall / light southwest winds / freezing level at 1000m

Avalanche Summary

A few size 1 windslab avalanches were reported from the Whistler area in response to windloading on Saturday. Expect significant wind slab activity with forecast weather.

Snowpack Summary

Not much happened in the way of snowfall over the past 2 days, but Mother Nature pummeled the Sea to Sky region throughout the week. Over 115cms of snow that fell since last weekend has now settled to about 80cm. Recent southwest winds have consistently hovered in the strong to extreme category and wind drifts have been reported up to 3 metres high. The recent storm snow is resting on a variety of older snow surfaces. These surfaces include previous cold, dry low density snow which may have had seen some faceting, old wind slabs, and crusts. These interfaces have most likely gained considerable strength, but it is reasonable to believe that any avalanche activity could step down to any of these interfaces. Previous concerns about deeper persistent weak layers appear to have diminished.Snowpack depths at treeline are in the region of 260 cm.

Problems

Wind Slabs

Heavy snowfall amounts and strong winds will set up stiff new wind slabs on lee slopes. Rising freezing levels will add cohesion to wind slabs adding to the likelihood of wider propagations.

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

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 5

Storm Slabs

Heavy amounts of storm snow have fallen on a variety of old surfaces. A deeper release is decreasing in probability, but would have a high consequence.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 5

Cornices

Strong winds and new snow have added mass to sensitive cornices. They may be destructive by themselves, and may also be a trigger for the slope below.

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

Elevations: Alpine.

Likelihood

Likely

Expected Size

1 - 6

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