Avalanche Forecast

Issued: Feb 20th, 2014 8:19AM

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

triley, Avalanche Canada

Kootenay Boundary.

Summary

Confidence

Fair - Forecast snowfall amounts are uncertain on Friday

Weather Forecast

Overnight and Friday: Light to moderate snowfall overnight bringing 5-10 cm of snow by morning. Freezing level dropping to valley bottoms overnight. Strong Westerly winds overnight becoming moderate Northwest during the day.Saturday: Broken skies with sunny periods and a chance of light flurries. Light Northwest winds.Sunday: Mostly cloudy with light snow and moderate Northwest winds. Alpine temperatures around -15.

Avalanche Summary

Widespread natural slab avalanche activity up to size 3.0 on all aspects and elevations. Remote triggering and long fracture propagations continue. Endless settlements and whumphing experienced while traveling on low angle terrain. Low elevation cut-blocks are releasing naturally at the February 10th interface.

Snowpack Summary

There is over a metre of recent storm snow that is sitting on a weak layer that is a mixture of facets, surface hoar, and melt-freeze crusts. The weak layer is widespread at all elevations and aspects. The storm slab continues to settle and become more cohesive allowing for longer fracture propagations and remote triggering. This persistent weak layer is expected to be a concern for some time; at least through the weekend.

Problems

Storm Slabs

Storm slab avalanches are expected to continue to release naturally at higher elevations and where the wind has transported snow. The storm snow may be very sensitive to human triggers at all elevations. Remote triggering is a concern.

Extra caution needed around cornices with current conditions.>The new snow will requires several days to settle and stabilize.>Avoid avalanche terrain during periods of heavy loading from new snow and wind.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

3 - 5

Persistent Slabs

Expect the deeply buried weak layer to continue to produce very large and destructive avalanches. Each load of new snow adds to the storm slab above the weak layer.

Avoid runouts where triggering slopes from below is possible.>Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>Avoid areas with overhead hazard.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

3 - 6

Valid until: Feb 21st, 2014 2:00PM