Bulletin d’avalanche

Sea To Sky

Nov 29 – 30, 2012Avalanche Canada
Voir sur la carte
Archivé · expiré 14 years ago

Danger d’avalanche

Sat
Sun
Alpin
4 · Fort
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré
Ouvrir la carte complète

Points saillants

Problèmes avalancheux

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely - Very Likely
    Taille
    1–5
    New snow at upper elevations will build storm slabs on all aspects, overlying a variety of weak surface layers. Storm slabs, and new wind slabs will be touchy, and natural avalanche activity is likely with heavy loading from snow and strong SE wind.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    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 - Intensity of incoming weather is uncertain

Weather Forecast

A deep low pressure system off the Gulf of Alaska will continue to bring moist, warm and an active weather pattern over the next few days. Weaker impulses embedded in the flow will bring moderate amounts of precipitation over the mountains. Timing of these pulses are tricky to predict. Friday: FLVL’s 1400 m, snow amounts 10-20 cm, ridgetop winds SE 40- gusting 60 km/hr, alpine temps -3.0.Saturday: FLVL’s 1200m, snow amounts up to 15 cm, ridgetop winds SE 40-50 km/hr, alpine temps -4.0. Sunday: FLVL’s 1000-1200 m, snow amounts 5-8 cm, ridgetop winds S 10 km/hr, alpine temps -4.0.

Avalanche Summary

No new observations today.Reports from the Whistler area on Tuesday include a Size 2.5 deep slab avalanche running on the early November facet/crust combo triggered with small explosives low on the slope. Check out Wayne Flann's Avalanche Blog for more information, including photos. Also of note, there was a report of a size 2.5 skier triggered avalanche on Saturday. This avalanche occurred on a northeast aspect in the alpine. It was triggered from the bottom of the slope, and likely released on the early November layer.Natural avalanche activity will be the theme over the forecast period.

Snowpack Summary

The region will continue moderate-heavy amounts of new snow, and strong winds. Storm slabs and fresh wind slabs will load a variety of weak surfaces. These (now buried) surfaces consist of large surface hoar, a thin sun crust, surface facets, moist snow, or preserved storm snow depending on elevation, sun and wind exposure, slope angle, time of day, and aspect. Below this, the mid-pack seems to be fairly settled, strong and bridging instabilities that may exist deeper.Under the mid-pack (80-130 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, 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.

Régions couvertes