Bulletin d’avalanche

Kootenay Boundary

Apr 17 – 18, 2016Avalanche Canada
Voir sur la carte
Archivé · expiré 10 years ago

Danger d’avalanche

Tue
Wed
Alpin
Sans niveau
Limite forestière
Sans niveau
Sous la limite
Sans niveau
Ouvrir la carte complète

Points saillants

Spring Conditions. Ongoing sunny weather and rapidly rising freezing levels will increase the likelihood of large destructive wet slab avalanches, especially if there is little or no overnight refreeze of the snow surface.

Problèmes avalancheux

  • Cornices

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    2–5
    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
    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
    Possible
    Taille
    3–6
    Rapidly warming temperatures and little to no overnight surface freeze will increase the potential for deep wet slab release.

Weather Forecast

MONDAY: Freezing Level: 3700m, sunny, light southerly winds. TUESDAY:  Freezing Level: 3700m, sunny, light westerly winds. WEDNESDAY:  Freezing Level: 3600m, sunny, light variable winds.

Avalanche Summary

No new avalanches reported in this region. Most commercial operations have closed for the season, and data is becoming sparse. However, with the forecasted warm up and lack of overnight surface freezing, I would expect cornice failures and sporadic large wet slab avalanches.

Snowpack Summary

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. Cornices are large, fragile, and could trigger deep slab avalanches that run to valley bottoms. 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.

Régions couvertes