Avalanche forecast

Kootenay Boundary

Dec 20 – 21, 2012Avalanche Canada
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Avalanche danger

Sat
Sun
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

If more than 20 cm new snow arrives by Friday morning with wind, bump danger levels up by one for all elevations.

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
    With slightly warmer temperatures, the new storm may develop a denser surface slab. Recent light snow may also be transported by forecast strong southwest winds into deep wind slabs on north through east aspects.

Confidence

Poor - Intensity of incoming weather is uncertain

Weather Forecast

Friday: Snowfall is expected to continue overnight Thursday but taper off Friday morning. Up to 10 cm can be expected by noon on Friday. Treeline temperatures are expected to be around -4C. Winds moderate southerly.Saturday: The region could see another good hit of snow Friday night, with a possibility for 10-15 cm of new snow by Saturday morning and maybe a little more during the day. Treeline temperatures falling to around -6. Winds gusting to around 60 km/h from the SW.Sunday: Flurries or light snowfall. Temperatures continuing their downward trend. Winds light southwesterly.

Avalanche Summary

On Thursday, machine-triggered avalanches were reported running at the base of the most recent storm snow down 20 to 50 cm. Explosive testing produced avalanche up to size 2.5 in the storm snow at elevations around 2000 m.On Wednesday, natural and skier-triggered avalanches up to size 2.0 were reported to be releasing down 30-50 cms in the storm snow.

Snowpack Summary

The most recent storm brought 20-40 cms of dry light snow combined with moderate to strong Southwest winds. The storm slab has been very easy to trigger in areas where the wind stiffened the slab a bit. In most places the slab is still soft to very soft and it is not propagating far. Expect heavy sluffing in steep terrain. The well settled mid-pack has not been showing shears in snow profile tests.

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