Bulletin d’avalanche

Northwest Coastal

Nov 24 – 25, 2012Avalanche Canada
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Archivé · expiré 14 years ago

Danger d’avalanche

Mon
Tue
Alpin
Sans niveau
Limite forestière
Sans niveau
Sous la limite
Sans niveau
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Points saillants

Technical Problems prevented us from updating the forecast today (Saturday). This forecast was first issued on Friday (Nov 23) and is based on information available at that time. We apologize for any inconvenience this may cause. 

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely - Very Likely
    Taille
    1–4
    Recent northerly and easterly winds have deposited weak slabs on unusual aspects. Natural avalanche activity is expected in response to heavy wind-loading, and fresh wind slabs will likely be sensitive to human triggering.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    2–5
    Facet/crust combinations can propagate over large areas, are often prone to remote triggering and step down avalanches, and typical trigger points include thin rocky areas.

Confidence

Poor - Due to limited field observations for the entire period

Weather Forecast

Overnight and Saturday: Strong SE winds overnight are expected to ease to moderate with strong gusts during the day Saturday. Alpine temps should lower to about -9.0 and remain cool through Sunday. Expect 5-7 mm overnight and an additional 8-12 mm on Saturday.Sunday: High pressure is moving on to the coast, but it looks like it will remain mostly overcast with some convective snow showers. Winds are expected to switch to the NW and remain moderate with strong gusts.

Avalanche Summary

Some touchy thin wind slabs 5-15 cms have been reported to be releasing in the new snow where it has been transported into a wind slab. Explosives control last weekend produced a couple of 30cm deep size 1.5-2 storm slab avalanches. Natural avalanche activity followed by human-triggered activity generally occurs with every intense weather period, such as what's forecast for Thursday night and Friday.

Snowpack Summary

Total snowpack depth are probably close to a metre in most treeline areas and deeper but more variable in the alpine, while below treeline areas are probably still below threshold depths for avalanches. A recent profile at 1200m in the Shames area showed a predominately "right-side-up" 120cm deep snowpack with a thin layer of facets sitting on a crust 35cm off the ground. An Extended Column Test produced produced easy (10 taps)  results on this persistent weak layer , but the resistant fracture didn't propagate across the entire column. Check out the Skeena/Babine discussion forum for more information from the area.

Régions couvertes