Avalanche Forecast

Issued: Feb 9th, 2013 8:45AM

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

pmarshall, Avalanche Canada

Kootenay Boundary.

If you're skiing or riding in the northern part of the region (e.g. Kokanee Glacier) make sure you check out the South Columbia forecast. It's a little trickier to the north where more recent snow accumulated.

Summary

Confidence

Fair - Timing or intensity of solar radiation is uncertain

Weather Forecast

Sunday: A ridge of high pressure should maintain dry conditions and sunny skies. The freezing level is around 1700 m with alpine temperatures around -2. Winds are light from the north. Monday: The ridge flattens resulting in increasing cloud throughout the day. The freezing level should be around 1400 m. Winds are light to moderate from the west-southwest. Tuesday: A stronger system should push through in the afternoon bringing light snowfall â€“ 5-10 cm. The freezing level is around 1000 m and winds are moderate to strong from the southwest. Â

Avalanche Summary

Reports from the region include a few size 1-1.5 natural or human triggered slab avalanches, mainly from north through east aspects. There were also reports of small loose dry or loose wet avalanches from steep terrain.

Snowpack Summary

The snow surface consists of a sun crust, surface hoar, or a dusting of new snow. Below this approximately 15-20 cm of recent storm snow has been redistributed into soft wind slabs at higher elevations. The new snow overlies a gamut of old surfaces which include: old wind slabs at higher elevations, fairly widespread surface hoar, and a melt-freeze crust on previously sun-exposed slopes. This interface will be something to watch as the overlying slab develops. About 35-50cm below the surface is another interface of surface hoar or a sun crust that was buried on Jan 23. It is hard to find in some areas and seems to be gaining strength where it is found, but this weakness is still on the radar of professionals in the region. The snowpack below this is generally well settled and bonded.

Problems

Wind Slabs

Triggering is possible in steep gully features and in lee of ridge crests.

Use ridges or ribs to avoid pockets of wind loaded snow.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Persistent Slabs

An assortment of weak crystals is buried between 35 and 50cm below the surface. Although this interface is gaining strength, triggering may still be possible in unsupported terrain.

Choose well supported terrain without convexities.>Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

1 - 4

Loose Wet

Loose wet avalanches are likely on steep south facing slopes if the sun is out in full force.

Watch for wet loose or slab activity with forecast rain and/or warm temperatures.>

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

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Feb 10th, 2013 2:00PM