Avalanche forecast

Kootenay Boundary

Dec 15 – 16, 2012Avalanche Canada
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Avalanche danger

Mon
Tue
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–4
    A soft slab on the surface is stiffening with with continued settlement and wind-exposure, and may be triggered by light additional loads like a skier or rider.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    2–5
    Slopes that roll over such that the slab is unsupported from below. Particularly in areas with a shallower snowpack.

Confidence

Fair - Intensity of incoming weather is uncertain on Monday

Weather Forecast

Overnight and Sunday: Light to moderate Southwest winds should become more westerly overnight and during the day Sunday. Very light precipitation should bring 1-3 cms during the day Sunday. Freezing level is expected to remain close to valley bottom and alpine temperatures should be -7.0.Monday: The next system is forecast to move into the region by Monday morning. Expect moderate precipitation overnight bringing 5-10 cms of snow by morning and another 10-20 cms during the day. Strong Southwest winds are forecast during the storm and the freezing level should remain close to the valley bottom.Tuesday: Cool and unsettled conditions in the wake of Mondays storm.

Avalanche Summary

There was one skier controlled release that was size 2.0 and ran on the late November surface hoar layer (Rossland Range).

Snowpack Summary

Reports from the Kootenay Pass and Whitewater areas are similar. Both areas have about 10-15 cms of loose snow that is bonding to another 20-30 cms of well settled snow below. The late November surface hoar continues to give results in snow profile stability tests. In the Rossland range, the late November surface hoar has not been buried by as much new snow, and continues to give sudden planar results in stability tests (when the bond between the layers fail, it fails suddenly and across the whole block that is being tested). The old surface hoar at the boundary between the slabs has been found to be intact and quite large in this part of the region. This well preserved layer may continue to react to increased loading from users or a new storm load.

Regions covered