Bulletin d’avalanche

North Columbia

Mar 17, 2017Avalanche Canada
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Archivé · expiré 10 years ago

Danger d’avalanche

Sat
Sun
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
3 · Marqué
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Points saillants

A momentary reprieve from the precipitation and high freezing levels on Friday. Yet we still have dangerous avalanche conditions. Saturday it will start all over with precipitation and warm temperatures forecast again.

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    2–4
    Several persistent weaknesses in the upper snowpack remain a concern. There is step-down potential resulting in large and dangerous avalanches.

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    2–3
    Weaknesses within the recent storm snow are susceptible to human triggering. These storm slabs are particularly deep and touchy on slopes loaded by southerly wind.

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2
    As temperatures slowly cool there may still be the lingering possibility of triggering loose wet avalanches that step down to deeper weak layers at lower elevations.

Confidence

Moderate - Intensity of incoming weather systems is uncertain on Saturday

Weather Forecast

FRIDAY: Scattered flurries / Moderate south wind / Alpine temperature -6 / Freezing level 1400mSATURDAY: Snow, accumulation 25-35cm / Moderate to strong southwest wind / Alpine temperature -3 / Freezing level 1800mSUNDAY: Broken skies with isolated flurries / moderate to strong west wind / Alpine temperature -10 / Freezing level 800mMore details can be found on theMountain Weather Forecast.

Avalanche Summary

The past 2 days have seen a widespread natural avalanche activity up to Size 4 at all elevations and on all aspects. Many of these triggered in the storm snow with some also stepping down to persistent weaknesses deeper in the snowpack. Widespread wet slabs and loose wet avalanches have also been reported below treeline. There was one report of size 4.5 avalanche in the central Selkirk range running during an intense snowfall and wind event very early Thursday morning. This was reported as a full depth avalanche running full path.

Snowpack Summary

Around 60-100cm of new snow has fallen at upper elevations over the past several days and has been redistributed by moderate to strong southerly wind. Warm temperatures on Sunday through Wednesday has resulted in moist and/or rain saturated snow on all aspects up to 2100m. There may now be a weak surface crust found between 1300 and 2100m. The snowpack below approximately 1300m is reported to be isothermic. The new snow sits on top of faceted snow as well as isolated small surface hoar in sheltered areas and a thin sun crust on steep southerly aspects. The persistent weakness buried late-February is now down 80-140 cm, and is composed of weak facetted crystals on a thick rain crust as high as about 1800m and facets on sun crust on steep southerly aspects. The mid and lower snowpack are well settled and stable in deeper snowpack areas, but may be weak and faceted in shallow areas. The deep mid-December facet layer still lingers in the northern part of the Monashees near Valemount.

Régions couvertes