Bulletin d’avalanche

Northwest Coastal

Feb 15, 2018Avalanche Canada
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Archivé · expiré 9 years ago

Danger d’avalanche

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

Snowfall amounts for Thursday are uncertain, if amounts received exceed forecasted values the avalanche danger will be "High".

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    2.5–4
    A weak layer exists 130-180 cm below the surface. It may still be possible for rapid loading from snow on wind to trigger this layer, or for a storm slab release to step down to this layer resulting in a very large avalanche.

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely - Very Likely
    Taille
    1–3
    Recent heavy snowfall and strong winds have formed widespread storm slabs that are both deep and reactive.

Confidence

Moderate - Forecast snowfall amounts are uncertain

Weather Forecast

THURSDAY: Snow. Accumulation 5-15 cm. Ridge wind moderate to strong, southwest. Temperature -6. Freezing level 300 m.FRIDAY: Mix of sun and cloud, light flurries. Accumulation up to 5 cm. Ridge wind light, south. Temperature -7. Freezing level 400 m.SATURDAY: Mix of sun and cloud. Ridge wind light to moderate, northeast. Temperature -9. Freezing level 200 m.

Avalanche Summary

Numerous professionals across the region are reporting that intense loading during Tuesday's storm triggered a widespread natural avalanche cycle up to size 3, with at least one avalanche running beyond it's historical runout distance.

Snowpack Summary

Approximately 40-60 cm of new snow has fallen across the region since Tuesday with the highest snowfall amounts in the Terrace area.This new snow sits on a wide array of surfaces - including wind scoured from strong and variable winds during the long weekend, and fresh wind slabs at higher elevations on lee (downwind) slopes as well as facets and surface hoar in sheltered locations at treeline and below, and suncrusts on steep solar aspects.A 5-20 cm thick crust that was buried early February and can be found 60-110 cm below the surface on all aspects up to 1400 m. A weak layer buried in mid-January is 120-150 cm below the surface and remains a concern. In most areas this layer is a crust, but it may also be surface hoar in sheltered areas at tree line and below. This layer may remain reactive as it adjusts to the weight of the new snow.In thinner snowpack areas (north and inland), deeper crust / surface hoar layers that were buried in December and early January may still be a concern. They are buried over 150 cm below the surface, but could still be reactive and triggered from shallow spots.

Régions couvertes