Avalanche Forecast

Issued: Feb 8th, 2013 8:37AM

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.

Summary

Confidence

Good

Weather Forecast

Synopsis: A ridge of high pressure off the coast of BC should maintain dry conditions and mainly sunny skies through the weekend and into next week. Patchy valley cloud is possible. Temperatures during the day should rise to around -2 at treeline. Winds are generally light from the northwest.

Avalanche Summary

Several natural and skier-triggered loose snow avalanches were reported in steep northerly terrain. There were only a couple reports of recent slab avalanches in the region. These were reported as size 1.5 human triggered avalanches, and despite their small size they picked up significant speed and ran surprisingly far.

Snowpack Summary

Approximately 15-20 cm of new 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. These surfaces will be something to watch as the overlying slab develops.About 35-50cm below the surface is an 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.

Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

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.

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

Expected Size

1 - 2

Valid until: Feb 9th, 2013 2:00PM