Avalanche forecast

Kootenay Boundary

Apr 21 – 22, 2018Avalanche Canada
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Avalanche danger

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

Warming and solar radiation will drive the avalanche danger in the coming days. Watch for conditions that change throughout the day, and be cautious of overhead hazards.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5
    Lingering wind slabs from Friday night may remain reactive in high elevation lee terrain. Watch for triggering behind ridgecrests and steep rolls.

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–3
    Warming and solar radiation may also cause large cornices to fail. Cornice failures may be dangerous by themselves, but they could also trigger a large avalanche on the slope below.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely - Very Likely
    Size
    1–2
    Warming and solar radiation over the next few days are expected to trigger loose wet avalanches, especially in steep, sun-exposed terrain. Loose wet avalanches can be pushy and entrain mass quickly.

Confidence

Moderate - Timing or intensity of solar radiation is uncertain on Sunday

Weather Forecast

A ridge of high pressure will develop for the forecast period bringing clear skies and light ridgetop winds. The freezing level will hover around 1800m on Sunday, 2400m on Monday and then 3100m on Tuesday.

Avalanche Summary

No new avalanches have been reported. I'm sure there was a round of wind slab activity on Saturday in response to Friday night's snow and wind, although I'm sure the new snow will settle and gain strength in the coming days. Loose wet avalanches and cornice falls are expected to become problematic with warming and solar radiation forecast for Sunday and Monday.

Snowpack Summary

New snow and wind from Friday night and Saturday likely formed relatively small wind slabs in upper elevation lee terrain. Depending on aspect and elevation, the new snow likely overlies a melt-freeze crust or settled storm snow from earlier in the week.Numerous other melt-freeze crusts exist in the upper snowpack from rain, sun, and warming during the spring season. The mid and lower snowpack are generally well-settled and strong while melt-freeze conditions exist on all aspects below treeline.

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