Bulletin d’avalanche

Northwest Coastal

Mar 18 – 19, 2016Avalanche Canada
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Archivé · expiré 11 years ago

Danger d’avalanche

Sun
Mon
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Points saillants

Extra caution is needed in areas in the northern part of the region where buried persistent weaknesses remain active.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–3
    Recently easterly outflow winds may have created fresh wind slabs in exposed terrain. 

  • Cornices

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    2–5
    Natural cornice releases are possible with sun exposure and warming. A falling cornice chunk could trigger a large slab on the slope below.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    3–6
    Persistent weaknesses have recently been reacting to cornice triggers in the northern part of the region. Keep these in mind if you're riding near Bear Pass or Ningunsaw Pass. 

Confidence

Moderate

Weather Forecast

SATURDAY: Mainly cloudy. The freezing level dips to 1300 m. Winds should be moderate from the S-SE. SUNDAY: Cloudy with a chance of flurries. The freezing level spikes back to 1600-1800 m and winds are light to moderate from the east. MONDAY: Cloudy with light snow. The freezing level is around 1200-1400 m and winds are light.

Avalanche Summary

On Thursday, there were reports of natural and explosive-triggered cornice falls, primarily from areas north of Stewart and near Ningunsaw Pass. Many of these triggered persistent slabs with the largest results (size 3-3.5) occurring on NE-NW aspects. Observations from the southern part of the region were limited, but one observer reported triggering storm slabs up to 20 cm deep (size 1-1.5) on north-facing slopes.

Snowpack Summary

Easterly winds have redistributed the surface snow forming fresh wind slabs in exposed terrain. On sheltered and shady slopes there is 20-40 cm of settled dry (and faceting) powder, possibly capped by surface hoar. On south aspects, the recent storm snow may be sitting on a sun crust. Lower elevations and south aspects are going through daily melt-freeze cycles. A layer of surface hoar or melt-freeze crust buried on March 3 is down 70-100cm and has been recently reactive in the areas north of Stewart. An older crust/facet layer buried in early February can now be found down over a meter but this layer has been dormant for several weeks.

Régions couvertes