Avalanche Forecast

Issued: Jan 10th, 2012 9:35AM

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

Avalanche Canada triley, Avalanche Canada

Summary

Confidence

Fair - Forecast snowfall amounts are uncertain on Thursday

Weather Forecast

The ridge of high pressure is expected to bring clear skies and colder temperatures to the region on Wednesday. The temperature in the alpine should be about -15.0 and the winds should increase to about 40 km/hr from the west-northwest. Cloud and light precipitation should move into the region from the Pacific during Wednesday evening, and should become moderate to heavy by late Thursday morning. This system is expected to bring 15-20 cm of snow to higher elevations near Terrace, 30 cm to the mountains near Stewart, and 5-10 cm to the Smithers area. The storm should have passed by Friday mid-morning when arctic air is expected to start to move into the region.

Avalanche Summary

A couple of loose snow avalanches up to size 2.0 from very steep terrain at higher elevations have been reported. There was one very large avalanche triggered by a large explosive charge above the highway and rail corridor; the avalanche released down to the ground.

Snowpack Summary

Some areas are reporting an alpine snowpack of 5 metres. In these areas the mid-december surface hoar is buried down about 250 cm with a well settled and strong 80 cm above. These deeper snowpack areas are reporting that there are no shears except in the top 50 cm of storm snow; and these shears on recent stellar crystal weakness are expected to bond within the next few days. Areas that experienced very strong winds during the recent storm may have thick windslabs that may take another couple of days to settle. The lower snowpack is generally well settled and strong.

Problems

Wind Slabs

An icon showing Wind Slabs
Wind slabs that developed during the storm will take a couple of days to settle and strengthen.

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 4

Storm Slabs

An icon showing Storm Slabs
The storm deposited a thick layer of new snow in areas that are protected from the wind, that may take a couple of days to bond to the old surface.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 4

Valid until: Jan 11th, 2012 8:00AM

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