Avalanche Forecast

Issued: Dec 16th, 2013 7:49AM

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

Peter, Avalanche Canada

Kootenay Boundary.

Northern parts of the region could see a little more snow over the next day or two, which could lead to locally higher avalanche danger. If more than 10 cm of new snow falls (with wind) expect considerable danger in the alpine.

Summary

Confidence

Fair

Weather Forecast

Tonight and Tuesday: Mainly cloudy with light precipitation ~ 5 cm. The freezing level is around 1200 m on Tuesday and winds are strong to extreme from the West. Wednesday: Mainly cloudy with continued flurries or light snow. The freezing level should drop back to valley bottom throughout the day and winds should ease to light from the NW. Thursday: Mainly sunny and cooler. The freezing level should be at valley bottom with moderate northerly winds.

Avalanche Summary

No avalanches have been reported in the last few days.

Snowpack Summary

In general, snowpack depths are below seasonal average any many slopes below treeline are reported to be below threshold for avalanche activity. Deeper snowpacks may exist to the north of the region.Light snowfall and strong West-southwest winds have formed pockets of soft wind slab in exposed areas above treeline. Recent snowfall overlies weak faceted crystals, small surface hoar or older hard windslabs in exposed high elevation terrain. Between 35 and 50cm below the surface you may find a weak layer of surface hoar on sheltered slopes and a melt-freeze crust on steep solar aspects. Most reports indicate this layer is "stubborn" to trigger, or there may not be a deep enough overlying slab to create a significant hazard. That said, I'd remain curious about this interface, especially as the snow load increases.There are reports of a deeply buried early season crust that formed in October, this layer is more likely to be found near the ground in the high alpine on northerly aspects. Little is known about its reactivity in this region.

Problems

Wind Slabs

Forecast strong or extreme westerly winds may create new wind slabs in exposed lee terrain and cross-loaded features at and above treeline.

Be cautious as you transition into wind affected terrain.>Avoid freshly wind loaded features.>Use ridges or ribs to avoid pockets of wind loaded snow.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Persistent Slabs

The late November surface hoar layer, now down 40-50 cm, may become more reactive with mild temperatures and continued loading.

Make observations and assess conditions continually as you travel.>Whumpfing is direct evidence of a buried instability.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 4

Valid until: Dec 17th, 2013 2:00PM