Avalanche Forecast

Issued: Feb 18th, 2015 8:36AM

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

Avalanche Canada jlammers, Avalanche Canada

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Summary

Confidence

Fair - Due to the number of field observations

Weather Forecast

A weak pacific frontal system will bring light snowfall (between 5 and 10cm) Wednesday night and into Thursday. A clearing trend is forecast for Friday and Saturday as a ridge of high pressure rebuilds in the eastern Pacific. Winds are expected to be strong from the southwest on Thursday, and then become moderate from the northwest on Friday and Saturday. Daytime freezing levels should hover around 1000m for the forecast period

Avalanche Summary

Sometime during the last few days, a natural cornice fall triggered a large slab avalanche in steep, rocky alpine terrain near Smithers. (see the latest Mountain Information Network post for pictures and more details) Loose wet avalanches to size 1.5 were also noted on Tuesday in response to warming and solar radiation. There will likely be a shift to new wind slab activity with snow and wind forecast for Thursday.

Snowpack Summary

In general, snow surfaces are highly variable. In the south of the region, melt freeze conditions exist below about 1800m. Above this you'll likely find settled wind slabs on north facing terrain, and a melt freeze crust on solar aspects. Between 15 and 40cm below the surface you may find weak surface hoar which was buried on February 10th. Although recent warming may have destroyed this potentially weak layer in some areas, I'd dig down and test for this layer at upper elevations where colder temperatures may have allowed for this weakness to persist. In general, the mid snowpack is strong and well-settled, and at the base of the snowpack, facets which formed earlier in the season have gone dormant for the time being. Cornices are reported to be large and unsupported.Further north in the region, slightly cooler temperatures have persisted and melt freeze conditions are not as widespread. In these areas deeper persistent weaknesses are more likely to exist.

Problems

Wind Slabs

An icon showing Wind Slabs
Light amounts of new snow and strong southwest winds are forecast to form new wind slabs in lee terrain. Watch for conditions that change throughout the day on Thursday.
Be cautious as you transition into wind affected terrain.>Be alert to conditions that change with elevation.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Feb 19th, 2015 2:00PM