Avalanche Forecast

Issued: Dec 9th, 2013 7:55AM

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.

esharp, Avalanche Canada

Kootenay Boundary.

Summary

Confidence

Fair - Due to the number of field observations

Weather Forecast

An arctic air mass is still sitting over much of BC however a series of fronts will start to drive the cold air out of the region through the week. Tuesday will be mainly cloudy, cool and calm. Wednesday will see light precipitation and light SW winds. This looks like it will continue into Thursday before tapering off Friday.

Avalanche Summary

Small natural windslab avalanches have been observed at treeline and in the alpine around Nelson.

Snowpack Summary

The recent cold temperatures have driven faceting in the upper snowpack and surface hoar growth is being reported in some areas. The snow that fell last week is sitting above a buried weak layer of surface hoar found on north facing slopes and a crust on steep solar aspects. In many places the upper snowpack has not yet settled into a slab. However, in open areas this snow has be redistributed by the recent north to east winds forming windslabs at ridge-top and in cross loaded features. There are reports of a deeply buried early season crust that formed in October, this layer is more likely to be found in the high alpine on northerly aspects.

Problems

Wind Slabs

Northeast winds redistributed the snow from last week forming wind slabs in lee features at ridgeline and on cross-loaded slopes. Don't let wind slabs in unusual places catch you by surprise.

Avoid travelling in areas that have been reverse loaded by winds.>Be cautious as you transition into wind affected terrain.>The best powder will be found in sheltered locations at or below treeline.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Persistent Slabs

The recent cold temperatures have hindered the settlement of the upper snowpack into a cohesive slabs in most places. However, it would be wise to treat large open slopes with suspicion

Avoid steep solar aspects were a crust may have formed>Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.>Dig down to find and test weak layers before committing to a line.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

2 - 4

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