Avalanche forecast

Kootenay Boundary

Apr 17 – 18, 2018Avalanche Canada
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Avalanche danger

Thu
Fri
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

Sun and warming will increase the likelihood of avalanches. Both loose wet and storm slab avalanches could be triggered naturally or by humans. Be particularly cautious on south slopes when it is sunny and avoid overhead exposure.

Avalanche problems

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2.5
    Up to 50 cm of snow fell recently, which may not bond well to an underlying crust. Slabs may be more reactive adjacent to ridges in wind-loaded terrain. Watch your overhead exposure, as cornices could trigger slabs on slopes below.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2.5
    Sunny skies and warming air temperatures will rapidly weaken the snow surface and increase the likelihood of triggering loose wet avalanches. Expect natural avalanches on steep slopes, particularly on south aspects under sunny skies.

Confidence

Moderate - Due to the number of field observations

Weather Forecast

WEDNESDAY: Sunny with afternoon clouds, light southeast winds, alpine temperature -3 C, freezing level 1700 m.THURSDAY: Sunny, light southwest winds, alpine temperature 1 C, freezing level 2200 m.FRIDAY: A mix of sun and cloud, light southwest winds, alpine temperature 1 C, freezing level 2200 m.

Avalanche Summary

On Monday, loose wet avalanches were triggered naturally and by explosives. They were large (size 2 to 2.5) and on all aspects between 1700 m and 2100 m.

Snowpack Summary

An additional 15 to 25 cm of snow fell on Tuesday, for storm snow totals of 30 to 50 cm since Monday morning. The snow fell on a melt-freeze crust produced from rain and warm temperatures on Sunday. Numerous other melt-freeze crusts exist in the upper snowpack from rain, sun, and warming during the spring season. The snowpack below this is generally well-settled and strong.At lower elevations below treeline, a spring snowpack exists.

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