Bulletin d’avalanche

Northwest Coastal

Jan 26 – 27, 2014Avalanche Canada
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Archivé · expiré 13 years ago

Danger d’avalanche

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

Problèmes avalancheux

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2
    Increasing cloud cover should reduce exposure to solar radiation making moist and wet snow avalanches less touchy to trigger. Mostly a problem on very steep southerly aspects.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    4–7
    Basal facets, buried surface hoar, and glide avalanches are all expected to become more sensitive to triggering with warm temperatures and solar radiation. Although tricky to pinpoint when and where they might occur, the consequences could be severe.

Confidence

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

Weather Forecast

Overnight and Monday: Continued warm air at higher elevations overnight and Monday morning. The inversion is expected to break down Monday afternoon or evening bringing more seasonal alpine temperatures. Mostly cloudy during the day with light Southeast winds.Tuesday: Freezing levels are expected to continue to drop from about 1500 metres in the morning to about 1000 metres in the afternoon. Mostly cloudy with light precipitation in the afternoon and Southwest winds building to moderate values.Wednesday: Cloudy with light precipitation and moderate Northwest winds.

Avalanche Summary

Reports of moist and wet point releases from very steep terrain on solar exposed aspects. Glide cracks are reported to be opening up and "creeping" down slopes, with a couple of glide avalanches releasing up to size 1.5.

Snowpack Summary

Reports tell us that there has not been much crust recovery at higher elevations due to the temperature inversion. The top 20-30 cm of snow in the alpine has been reported as isothermal in some areas. Melt-freeze crusts have been developing at lower elevations due to temperature fluctuations with overnight low temperatures dropping below freezing. New surface hoar has been reported on slopes that are sheltered from the sun at and below treeline. Some very sheltered alpine north aspects are facetting near the surface. A well settled mid and lower snowpack may rest on basal facets, especially in thin snowpack areas at higher elevations.

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