Bulletin d’avalanche

Northwest Coastal

Nov 27 – 28, 2013Avalanche Canada
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Archivé · expiré 13 years ago

Danger d’avalanche

Fri
Sat
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré
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Points saillants

A new storm is expected to add some load to the shallow weak early season snowpack. New storm slabs may be easy to trigger, and deeply buried weak layers may not support the added load.

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    2–5
    The added load of new storm snow may cause this layer of concern to become more reactive. Avalanches that release on this layer may be large and destructive.

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–4
    Forecast strong winds and new snow are expected to develop new storm slabs.

Confidence

Fair - Forecast snowfall amounts are uncertain on Thursday

Weather Forecast

Overnight and Thursday: Models are showing about 20 mm of precipitation for near coastal areas by early morning. Strong South-Southwest winds are expected to reach 80 km/hr in the alpine. Light precipitation is forecast to continue on Thursday. Freezing level should be about 1500 metres at the beginning of the storm and slowly drop to 800 metres by Thursday afternoon.Friday: 5-10 mm of precipitation is forecast with continued strong Southwest winds and freezing levels rising to about 1200 metres during the day.Saturday: Very light precipitation combined with moderate Southwest winds that should change to light Northerly late in the day. Freezing level should drop to valley bottoms by Saturday evening.

Avalanche Summary

No new avalanches reported. Expect new storm slabs to develop during the storm. The added load of new snow and wind transported snow may overload the weak layer where the buried crust exists near the ground.

Snowpack Summary

Reports of extensive wind transport since the end of the November 23rd storm. There is a little more than a metre of snow at 1000 metres elevation, and the snowpack has been described as "generally moist" below this elevation. Snowpack tests resulted in moderate planar results down about 20 cm, and hard planar results on the early season crust down about 90 cm. These layers of concern may persist or become more reactive with the forecast snow load in the next few days. New storm slabs are expected to develop due to the forecast strong winds and new snow.

Régions couvertes