Avalanche Forecast

Issued: Dec 10th, 2013 8:44AM

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.

bcorrigan, Avalanche Canada

Kootenay Boundary.

Summary

Confidence

Fair - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

The cold arctic air will slowly be replace by relatively warmer air in the next few days as a Pacific frontal system moves onto the coast and inland.Wednesday: Light flurries, ridge top temperatures -5 to -10, winds light to moderate from the south southwest, freezing level at valley bottom.Thursday: Light to locally moderate precipitation, freezing levels at valley bottom, ridge top temperatures -5 to -10

Avalanche Summary

Small natural wind slab 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 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. In the alpine and at some tree line locations the snow has been redistributed by the recent north to east winds forming wind slabs at ridge-top and cross loading some 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

Wind slabs at tree line and above are still a concern. North east winds have created slabs in areas not usually seen. Use caution on all slopes at tree line and above.

Be cautious as you transition into wind affected terrain.>Avoid travelling in areas that have been reverse loaded by winds.>Avoid cross loaded slopes at or above treeline.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Persistent Slabs

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

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

2 - 4

Valid until: Dec 11th, 2013 2:00PM