Avalanche forecast

Kootenay Boundary

Jan 30 – 31, 2016Avalanche Canada
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Avalanche danger

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

New storm slabs may continue to be reactive, and deeply buried persistent weak layers may continue to be triggered in isolated terrain features.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    3–5
    This persistent weak layer is probably now best described as a low probability but high consequence problem. Dig down (80-120 cm) to see if the surface hoar exists in your area.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–3
    Recent storm slabs and pockets of wind slab may continue to be easy to trigger where they are sitting on buried surface hoar. Storm slabs may be well bonded where they are sitting on a thin rain crust.

Confidence

High

Weather Forecast

Unsettled with flurries or periods of light snow overnight combined with moderate westerly winds. Expect 3-5 cm by Sunday morning, and not much more accumulation during the day on Sunday. Freezing levels staying below about 500 metres on Sunday as the winds become light from the northwest. Some chance of broken skies on Sunday producing brief periods of moderate solar radiation. Overcast with convective flurries on Monday with light winds and alpine temperatures around -10. Tuesday should be a bit cooler with light winds and broken to scattered cloud.

Avalanche Summary

Some small natural wind slab or storm slab avalanches up to about 20 cm deep were reported on Saturday from the south of the region. On Friday a couple of operations reported natural slab avalanches up to size 2 that were releasing as pockets of wind slab or thin storm slab. Explosives controlled avalanches up to size 2.0 releasing in the storm snow were also reported on Friday. No new reports of any avalanches releasing down to the persistent weak layers.

Snowpack Summary

There was another 5-10 cm of new snow on Saturday morning that had been transported by moderate westerly winds overnight. This new snow has added to the 10-20 cm of new snow that was reported on Friday. The total recent storm slab of 15-30 cm may be sitting on a layer of surface hoar that was buried on January 27th, or on top of one or two thin freezing rain crusts up to about 2100 metres. Some areas report that previous strong winds destroyed this new layer of surface hoar, and may have stripped the old surface back to a hard rain crust before the new storm snow arrived. The persistent weak layer that was buried January 4th is now down 80-120 cm and continues to give sudden planar fractures in snowpack tests in some areas.

Regions covered