Avalanche Forecast

Issued: Mar 22nd, 2013 9:57AM

The alpine rating is considerable, the treeline rating is moderate, and the below treeline rating is moderate. Known problems include Storm Slabs and Loose Wet.

jfloyer, Avalanche Canada

Kootenay Boundary.

Recent avalanches big enough to bury or injure a person have been triggered on a buried crust. Maintain a cautious approach to travel this weekend.

Summary

Confidence

Fair - Timing or intensity of solar radiation is uncertain

Weather Forecast

Synopsis: Generally very fine weather with cool overnight temperatures and warm, sunny days.Saturday: Cloud lingering, but also some clear breaks. No precipitation. Freezing level 1400 m. Mostly light, but occasionally gusty, northerly winds.Sunday and Monday: Clear and sunny. Freezing level around 1600 m. Light southwesterly winds.

Avalanche Summary

On Thursday, several size 1.5-2 avalanches were either deliberately ski-cut or accidentally triggered on a range of aspects at elevations from 1800 - 2100 m. All failures were on a crust, typically buried 20-40 cm deep. Explosive avalanche control produced similar results.

Snowpack Summary

Between 20 and 60 cm recent storm snow rests on a thick crust that exists up to ridge top. The bond between the storm snow and the crust appears to be poor above 1800 m. In some places, you may find an additional, thinner crust within the top 60 cm snow. A buried surface hoar layer lies buried approximately 80 cm below the surface and continues to fail in a sudden planar fashion when tested. However, in most places it is likely not a concern due to the thick supportive crust that lies above it. Potentially large fragile cornices loom over many slopes.

Problems

Storm Slabs

Snow has been reacting readily to human triggers on a buried crust around 40 cm below the surface.

Choose well supported terrain without convexities.>Avoid freshly wind loaded features.>Give cornices a wide berth when travelling on or below ridges.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 4

Loose Wet

Solar aspects are likely to see loose snow avalanches on solar aspects when the sun comes out and temperatures start to warm. There is a danger that surface avalanches may step down to pull out slabs on the buried crust.

Avoid steep Southerly aspects.>Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>

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

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 3

Valid until: Mar 23rd, 2013 2:00PM