Bulletin d’avalanche

Kootenay Boundary

Apr 8 – 9, 2016Avalanche Canada
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Archivé · expiré 10 years ago

Danger d’avalanche

Sun
Mon
Alpin
Sans niveau
Limite forestière
Sans niveau
Sous la limite
Sans niveau
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Points saillants

Spring Conditions. Expect avalanche hazard to increase throughout the day, especially during periods of warm, sunny weather. Failing cornices could trigger large avalanches running to valley bottoms. Watch out for what's above your head.

Problèmes avalancheux

  • Cornices

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    3–6
    If the sun is shining, cornices present a significant hazard. Even if they don't trigger a slab avalanche when they fall onto a slope, they have a nasty habit of running surprisingly long distances.

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–3
    Solar radiation in the spring can rapidly change the hazard from low to high. Plan ahead and monitor the effect of solar radiation carefully.

  • Wet Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely
    Taille
    3–6
    Rapid warm ups can awaken dormant weak layers deep in the snowpack.

Weather Forecast

SATURDAY: Freezing level: 3000m, sunny, light southwest ridgetop winds. SUNDAY: Freezing level: 2500m, sunny, light southwesterly ridgetop winds. MONDAY: Freezing level: 2500m, sunny, light southwesterly ridgetop winds.

Avalanche Summary

On Thursday there was a widespread wet loose natural avalanche cycle reported to size 2 on all aspects/elevations.

Snowpack Summary

Cornices are large, fragile, and could trigger deep slab avalanches that run to valley bottoms. Monitoring the overnight freeze of the snow surface is very important during the spring. If the snow surface does not freeze overnight or if the crust is only a few cm thick, the effect of daytime heating and solar radiation will weaken the snowpack much more quickly than it would if there is a well frozen thick crust. This is because the crust must first melt before the sun can weaken the snowpack. Deeply buried weak layers in the mid snowpack and near the ground still have the potential to wake up and become active with a rapid warm up. While unlikely, releases on these deeply buried weak layers would result in very large avalanches. Glide cracks are widespread, active, and best avoided. Low elevation and thin snowpack areas have become isothermal, meaning the snowpack is 0 degrees Celsius throughout. An isothermal snowpack is more prone to full depth wet slab avalanches during the heat of the day.

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