Bulletin d’avalanche

Northwest Coastal

Apr 11 – 12, 2014Avalanche Canada
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Archivé · expiré 12 years ago

Danger d’avalanche

Sun
Mon
Alpin
4 · Fort
Limite forestière
4 · Fort
Sous la limite
4 · Fort
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Points saillants

Winter transitions into spring! Rapid warming and intense solar radiation can increase the avalanche danger quickly. Check out the new Forecaster Blog which is directly focused on the Northern Regions.

Problèmes avalancheux

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely - Very Likely
    Taille
    1–6
    Snow driven by strong winds have built storm and wind slab problems at higher elevations. Warmer temperatures and solar radiation will initially de-stabilize the new snow and likely activate a natural avalanche cycle. Cornices may fail with warming.

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely - Very Likely
    Taille
    1–4
    With warming and intense solar radiation a loose wet avalanche cycle will be likely, especially on solar slopes.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    3–7
    Persistent weak layers exist in the snowpack. These weak layers could be activated by cornice fall, a surface avalanche in motion, or a rapid warm-up. Avalanches failing on these weak layers will be large and destructive.

Confidence

Fair - Timing or intensity of solar radiation is uncertain on Saturday

Weather Forecast

A strong ridge, with a northwest flow dominates the region bringing clear skies and rapidly rising freezing levels. Saturday: Mainly sunny. Alpine temperatures high of 7.0 degrees. Ridgetop winds light from the NW. Freezing levels near 1700 m rising to 2000 m overnight.Sunday: Mainly sunny skies. Alpine temperatures high of 9.0 degrees and freezing levels rising to 2000 m. Ridgetop winds light from the SW.Monday: Mainly cloudy with isolated precipitation. Alpine temperatures high of 9.0 degrees and freezing levels 2400 m. Ridgetop winds light from the SW.

Avalanche Summary

Numerous loose wet naturals, and wet slabs were reported up to size 2 from steeper start zones at treeline and below treeline. Natural avalanche activity will likely continue through the weekend with sunny skies and a rapid rise in freezing levels.A widespread natural avalanche cycle up to size 4 occurred over the past 5 days and deep persistent weak layers became overloaded, initiating very-large avalanches. In shallower snowpack areas, storm slab avalanches have stepped down to the December facet/ depth hoar layer.

Snowpack Summary

The recent storm has brought 90+ cm or more too coastal regions (80-120 mm) forming thick storm slabs and wind slabs on leeward features. Warmer temperatures have helped to settle the recent snow. At lower elevations the snowpack has become moist, wet and saturated from rain. Large cornices have formed and loom over slopes below.Several persistent weak interfaces exist deeper in the snowpack. The early March layer can be found down 75 -140 cm. The early February layer is down 150 - 240 cm. These layers have become overloaded and are failing in some places initiating very-large avalanches.

Régions couvertes