Avalanche forecast

Kootenay Boundary

Feb 10, 2018Avalanche Canada
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Avalanche danger

Sun
Mon
Alpine
4 · High
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

Heads up! Large avalanches from above have the potential to reach run-out zones.Special Avalanche Warning in effect for the interior ranges. Copy this address to view details: http://bit.ly/2nSOUyX

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    2–4
    The snowpack is complex and continues to produce very large avalanches on several weak layers buried below the surface.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely - Very Likely
    Size
    1–3
    Storm slabs are reactive. Natural avalanche activity may taper off, but slopes are primed for human triggers. The first hit of sun will likely trigger loose dry avalanches which could step down to deeper layers.

Confidence

High -

Weather Forecast

The weather pattern has taken a dramatic shift as the arctic ridge becomes the dominant weather feature through the weekend, bringing colder temperatures and mostly clear skies.Saturday: Mostly sunny. Alpine temperatures near -8 and freezing levels at valley bottom. Ridgetop winds light from the West. Sunday: Mostly cloudy. Alpine temperatures near -9. Ridgetop winds light from the northwest.Monday: A mix of sun and cloud. Alpine temperatures -10. Light winds from the northeast.

Avalanche Summary

On Thursday, numerous large and destructive natural slab avalanches occurred through the region up to size 4 on all aspects and elevations. Avalanche control using explosives triggered numerous loose wet avalanches up to size 2 and a significant size 3 storm slab avalanche. These were reported from SE-SW slopes above 1900 m. Natural avalanche activity may spike again with the first hit of sun then start to taper off through the weekend with colder temps; however,  slopes will remain primed for human triggers.

Snowpack Summary

Storm snow accumulations vary, showing 10-45cm across the region at upper elevations. Below 1800 m a surface crust exists. The new snow in the alpine has been redistributed to leeward slopes from strong northwest winds. This now brings 1- 2 m of settled snow sitting on three significant surface hoar/ crust layers that were formed early to mid-January, and back in December. Near the base of the snowpack a crust/ facet interface exists and will likely haunt us all season. These persistent weak layers that lurk within the snowpack are reactive, producing large and destructive avalanches. The snowpack is extremely complex and requires respect and diligence at this time.

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