Avalanche forecast

Kootenay Boundary

Dec 19 – 20, 2012Avalanche Canada
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Avalanche danger

Fri
Sat
Alpine
4 · High
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

Avalanche problems

  • Loose Dry

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–5
    Loose dry snow remains unconsolidated in terrain that is protected from the wind. There is a lot of new snow; sluffing may entrain enough snow to bury a skier/rider.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    2–5
    The new storm is expected to develop a thick slab on all aspects and at all elevations. Recent light snow may also be transported by forecast strong Southwest winds into deep wind slabs on North thru East aspects.

Confidence

Fair - Forecast snowfall amounts are uncertain on Thursday

Weather Forecast

Overnight and Thursday: Strong Southerly winds and moderate to locally heavy precipitation 15-20 mm by morning that will be snow at all elevations (30-40 cms). This storm is expected to continue during the day; however snow fall amounts vary between models. This bulletin is based on another 15-20 mm (20-40 cms at higher elevations) of precipitation before the storm moves out of the region to the East. Freezing levels are expected to remain at valley bottoms except a brief period on Thursday where they may rise to just above valley bottoms.Friday: Light flurries are expected in the wake of the storm as residual moisture collides with the cold air moving in from the North. Expect winds to shift to the East-Northeast during the day.Saturday:Continued flurries for the areas near the U.S. border are expected to accumulate another 5-10 cms during the day. Alpine temperatures near -10.0 with light Southeast winds.

Avalanche Summary

Natural soft slab and loose snow avalanches up to size 2.0 were reported to be releasing down 30-50 cms in the storm snow. Large explosive triggers released loose snow avalanches up to size 2.5 in the Kootenay Pass area.

Snowpack Summary

Recent storm snow has been mostly unconsolidated with no reported new shears. The new storm may have more wind, and may quickly transport all of the available snow into new wind slabs. The wind with the new storm may not bond well to the old surface. It will be important to evaluate the bond and test the amount of force required to cause a shear between these two layers. Skiing and riding conditions have been reported to be very good, but this may change overnight depending on how the new storm and wind transported snow interfaces with the recent storm.

Regions covered