Bollettino valanghe

Sea To Sky

Dec 1 – 2, 2012Avalanche Canada
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Archiviato · scaduto 14 years ago

Pericolo valanghe

Mon
Tue
Alta quota
4 · Forte
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato
Apri la mappa completa

In sintesi

Problemi valanghivi

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely - Very Likely
    Dimensione
    1–5
    New storm slabs and wind slabs are building at higher elevations. Natural and rider triggered avalanches are likely; especially on lee slopes, and behind terrain features that have been wind loaded.

  • Deep Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely - Possible
    Dimensione
    2–6
    Slopes with smooth ground cover and reloaded bed surfaces may be prone to remote triggering and step down avalanches. Typical trigger points include thin rocky areas. May be difficult to trigger, but often very large with serious consequences.

Confidence

Poor - Timing, track, or intensity of incoming weather is uncertain on Tuesday

Weather Forecast

The recent weather pattern continues, with a very persistent deep low off the coast driving a moist, mild SW flow over the region. Moderate accumulations are expected through the forecast period, accompanied by moderate S-SW winds. Sunday: Fzlvl’s 1200 m, snow amounts 5-10 cm, ridgetop winds SE 15-25 km/hr, alpine temps -4.Monday: Fzlvl’s 1200 m, snow amounts 8-15 cm, ridgetop winds S 35 km/hr, alpine temps -4.Tuesday: Fzlvl’s 1700 m in the am then falling to 900 m in the afternoon, snow amounts 10-15 cm, ridgetop winds S 30 km/hr, alpine temps -3 falling to -8.

Avalanche Summary

Explosive testing produced numerous size 1-1.5 slab avalanches on NW-N aspects. All instabilities reacting within the storm snow.

Snowpack Summary

Storm slabs and fresh wind slabs have loaded a variety of weak surfaces. These (now buried) surfaces consist of large surface hoar, a thin sun crust, and surface facets. Below this, the mid-pack seems to be fairly settled, strong and bridging instabilities that may exist deeper.Under the mid-pack (90-150 cm down) sits the early November facet/ crust persistent weakness. Recent snowpack tests have shown sudden collapse (or "drops") results on the early November facet/crust deep persistent weakness, but because this weakness is so close to the ground in most areas, any associated avalanche activity will likely be limited to slopes with smooth ground cover (e.g. scree slopes, rock slabs, summer firn, glaciers, etc.). Areas that are most susceptible to trigger this deep persistent weakness are shallow, thin and variable snowpack deposition spots.To view a recent snow pit profile from the Spearhead Range, check out the Wayne Flann Avalanche Blog.

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