Avalanche Forecast

Issued: Feb 18th, 2012 9:52AM

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

Avalanche Canada ghelgeson, Avalanche Canada

Summary

Confidence

Good

Weather Forecast

We're entering a more active pattern which should persist through the middle of next week.Sun: A ridge of high pressure rebuilds during the day allowing temperatures to cool slightly while winds ease and switch from the SW to NW. A bit of instability from Saturday's storm will produce the odd flurry, but skies should clear in the afternoon. Look for 1500m temps to climb to -2 during the day.Mon/Tue: A few weak systems pass over the region favoring west slopes. Nothing in the flow is particularly well organized, it's the kind of setup that has the potential to bring 5-10 cm a day. Precip totals will be quite variable throughout the region. 1500 m temps: High -3, Low -7

Avalanche Summary

Activity continues to be limited to thin windslabs in wind exposed locations and sluffing in wind sheltered locales.

Snowpack Summary

Five centimeters fell overnight Friday which makes for 10 of light density snow above the February 16th Surface Hoar. 20 cm of light density snow lies between the February 16th surface hoar and the February 8th weakness. Within that 20cm some places have at least one other layer of surface hoar that formed between snowfalls. Feb. 8th is used to describe a combination of weak layers: In most locations it marks a widespread surface hoar layer. On steep south & west facing aspects a crust that formed during the drought was also buried on Feb. 8th. This crust likely has a bit of faceting below it too, meaning that most terrain in the region has a weak layer 20 - 25 cm under the snow surface. Down below this problematic interface a well settled mid pack is in place. The exception is the eastern and southern parts of the region where deeper weaknesses and basal facets may still be a factor. In these areas, a low-probability/high-consequence condition exists. It should be noted that large cornices remain widespread throughout the region.

Problems

Wind Slabs

An icon showing Wind Slabs
Fri/Sat winds were out of the S, SW. Winds switch to the NW Sun. This combination has made for thin windslabs in wind exposed terrain features.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Loose Dry

An icon showing Loose Dry
Watch for sluffing in wind sheltered locations. While largely manageable, sluff's could knock you off your feet.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Cornices

An icon showing Cornices
Cornices may weaken and fall off naturally due to the effects of day time warming and overnight cooling.

Aspects: North, North East, East.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 4

Valid until: Feb 19th, 2012 9:00AM

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