Bulletin d’avalanche

Northwest Coastal

Dec 17 – 18, 2013Avalanche Canada
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Archivé · expiré 13 years ago

Danger d’avalanche

Thu
Fri
Alpin
4 · Fort
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré

Points saillants

Heavy precipitation and high winds will keep the hazard high until the storm snow gets a chance to bond.

Problèmes avalancheux

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–4

Confidence

Fair - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

Wednesday: Pacific frontal system exits the area and moves off to the east. Freezing levels drop to valley bottom for most of the forecast area in between storms.Thursday: Freezing levels will rise late in the day to 1500 M as the next storm system drives onto the coast bringing high winds and heavy precipitation. Friday:  Pacific frontal system moves through the coast and into the interior.  Freezing levels lower as the storm moves east  but will stay above 0c for the coast, precip. will remain light.

Avalanche Summary

Numerous size 2-3 avalanches have been observed in the bear pass area. These mainly occurred on north through east slopes that are lee to strong southwest winds.The warm new snow is likely not bonding well to the weak layers formed in early December. Heightened avalanche activity and conditions will continue through Wednesday. Lower elevations are experiencing moist or wet natural avalanches releasing at or near the ground. This will become less of a problem once the freezing levels start descending back down to valley bottoms. Lee slopes will be touchy at upper elevations until this storm snow gets a chance to bond.

Snowpack Summary

Heavy wet snow has fallen at upper elevations with freezing levels rising to 1500m during the last storm. Strong west winds have transported the new snow creating storm slabs that sit above a weak layer formed during the last cold snap. Surface hoar, and facets in the upper snowpack are now buried anywhere from 50 to 80cm from the surface by the recent stormShames area at 950m elevation suggested the mid and lower snowpack was composed of various faceted layers and a stiff 4 cm crust. Another crust can be found closer to the base of the snowpack. The recent precipitation will strengthen the snowpack at lower elevations, but may prove to be problematic with rapid wind loading at upper levels.

Régions couvertes