Avalanche Forecast

Issued: Dec 26th, 2015 10:18AM

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

ghelgeson, Avalanche Canada

Kootenay Boundary.

Strong SW wind forecast for Saturday night and Sunday should add a touch of cohesion to the storm snow in wind exposed terrain. Carefully assess wind effect before committing to your line.

Summary

Confidence

Moderate - Wind speed and direction is uncertain on Sunday

Weather Forecast

A major storm has made landfall on the coast which should drive increasing winds and scattered flurries in the Kootenays. SATURDAY NIGHT: Moderate to strong W/SW winds. SUNDAY: Isolated convective flurries but no significant accumulations expected, freezing level at valley bottom, strong SW winds at ridgetop. MONDAY: Isolated flurries, but no significant precipitation expected, freezing level at valley bottom, light variable winds. TUESDAY: No significant precipitation expected, freezing level at valley bottom, light variable winds. For more detailed mountain weather information visit: avalanche.ca/weather

Avalanche Summary

Recent avalanche activity has been limited to fast running loose snow avalanches on steep features and small wind slabs in the alpine.

Snowpack Summary

Cold temperatures are beginning to facet the snow surface which may be problematic down the line. In the last week the region received 35 to 70cm of storm snow is that slowly settling into a very soft slab. In some places this slab rests on the mid-December weak layer. This layer is just a crust in most locations, but in Kootenay Pass there is a surface hoar interface on or just above this crust that is most prevalent between 1800 and 2000m. At treeline the early December crust is down around 70 to 110cm, and it's thick and supportive nature is likely capping any deeper weaknesses in most places. However, recent observations from the Nelson area indicate that there are facets on this crust, so it's an interface to watch as we move into the New Year. The lower snowpack is thought to be well settled.

Problems

Wind Slabs

Strong SW wind Sat. night/Sunday should add a touch of cohesion to the storm snow in wind exposed terrain. Fresh wind slabs may be sensitive to human triggering and natural failure Sunday. Carefully assess wind effect before committing to your line.

Exercise extra caution around recently wind loaded features and use ridges/ribs to sneak around these problem areas.>Be aware of pockets of buried surface hoar at treeline, especially around Kootenay Pass. There, open slopes and convex rolls at treeline are potential problem areas.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Loose Dry

Cold temperatures are faceting the snow surface which is leading to a small loose snow avalanche problem.

Be cautious of sluffing in steep terrain.>On steep slopes, pull over periodically or cut into a new line to manage sluffing.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Dec 27th, 2015 2:00PM