Bulletin d’avalanche

Northwest Coastal

Apr 22 – 23, 2012Avalanche Canada
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Archivé · expiré 14 years ago

Danger d’avalanche

Tue
Wed
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–4
    Thin new wind slabs may continue to develop from light precipitation and southwest winds.
  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–4
    Loose wet avalanches are most likely during periods of warming from rainfall or sunshine. These can push you around, entrain mass and become surprisingly large.
  • Wet Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    2–6
    Warm temperatures or rain may continue to weaken the snowpack, leading to full-depth releases. Loose wet slides may step down and propagate larger avalanches.

Confidence

Fair - Due to limited field observations on Monday

Weather Forecast

A weak Pacific front is expected to approach the Northwest from the south on Sunday. Light precipitation is expected during the day with moderate southeast winds and freezing levels rising to about 1500 metres. A ridge of high pressure is expected to develop on Monday bringing mostly clear skies and drier conditions with light winds.

Avalanche Summary

Spring conditions exist in the region. Exposure to the sun, warm temperatures, and periods of rain are the most likely factors to influence the avalanche danger. If the temperatures go below freezing overnight, strong crusts should develop that are likely to hold the snowpack together. If the sun shines for a few hours, the crusts may break down quickly and moist surface snow avalanches may start running naturally. Continued warming from more sun, rain, or no overnight freeze, may cause surface avalanches to step down and trigger deeper wet slab avalanches. Prolonged warming may cause very deep releases on weak layers that were deposited early in the season, or on depth hoar that developed during the winter. It is important to monitor the temperature and the freezing levels as they may change rapidly from day to day.

Snowpack Summary

As we transition into spring, the surface layers have a great deal of influence on the snowpack. When there is a solid re-frozen surface crust, travel is fast and easy, and the snowpack is held together by the surface cap. Any deeper persistent weak layers are unlikely to fail until the surface cap breaks down from daytime heating. When there is no crust, surface layers and any deeper weak layers may fail, depending on the amount of heat and the triggering force that is applied. If it cools off and snows, new snow and wind slabs may not bond well to the hard spring crusts. For more information on Spring Conditions and ways to mitigate risk, please visit the new Forecasters' Blog Post.

Régions couvertes