Bulletin d’avalanche

Northwest Coastal

Feb 25 – 26, 2014Avalanche Canada
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Archivé · expiré 13 years ago

Danger d’avalanche

Thu
Fri
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
3 · Marqué
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Points saillants

Forecast sun and high freezing levels may increase the danger from loose wet avalanches and avalanches stepping down to the deeply buried weak layer.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–4
    Northerly or Easterly outflow winds may reverse load slopes that have been previously stripped of storm snow. These ne wind slabs may be triggered by forecast solar radiation.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely - Very Likely
    Taille
    1–5
    The early February persistent weak layer continues to be sensitive to any additional load. Forecast solar radiation may trigger another round of natural activity on the buried weak layer.

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–3
    Forecast solar radiation may release moist or wet snow from steep Southerly aspects. Wet snow in motion may step down to deeply buried weak layers.

Confidence

Fair - Timing or intensity of solar radiation is uncertain

Weather Forecast

Overnight and Wednesday: Expect strong East to Southeast outflow winds with sunny skies and no precipitation. The freezing level should be down to valley bottoms overnight and then rise quickly to about 2000 metres.Thursday: Continued warm air at Alpine elevations with moderate outflow winds, mostly sunny skies, and no precipitation.Friday: Mix of sun and cloud with a chance of flurries. Winds becoming strong Northerly.

Avalanche Summary

Natural avalanches up to size 3.0 were reported from several areas of the region due to reverse loading from the outflow winds above the early February persistent weak layer. Forecast strong solar radiation and high freezing levels may cause moist or wet avalanches on Southerly aspects.

Snowpack Summary

Strong N-SE outflow winds have resulted in reverse loading and cross loading in exposed terrain at all elevations, and have scoured exposed windward slopes. The prominent mid February persistent weakness (surface hoar, facets, crust and/or wind pressed surfaces) is down 60-100 cm in the north and 120-160 cm in the south. Snowpack tests are now giving moderate to hard "pops or drops" shears on this weakness, and several whumpfs are still being reported. Basal facets and/or depth hoar remain a concern in shallow snowpack areas in the northern part of the region. Cornices are also large and may become weak if northerly winds start to undercut them.

Régions couvertes