Bulletin d’avalanche

Sea To Sky

Feb 22 – 23, 2012Avalanche Canada
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Archivé · expiré 15 years ago

Danger d’avalanche

Fri
Sat
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré
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Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–4
    Strong winds and new snow have likely created wind slabs in the alpine on NW-E aspects. These wind slabs are likely sensitive to rider triggers.

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–4
    Storm slabs will continue to grow with forecast snow. They may be particulary reactive where they exist in combination with buried crusts.

Confidence

Fair - Intensity of incoming weather is uncertain on Friday

Weather Forecast

A ridge of high pressure builds off the coast bringing mainly dry, cool conditions with possible scattered flurries on Thursday. Ridgetop winds will blow 30km/her from the NW. Freezing levels may rise to 1200m. On Friday a low pressure system arrives off the coast bringing moderate-heavy precipitation amounts. Snow amounts near 15-25cm. Freezing levels fall to valley bottom. Ridgetop winds strong from the WNW. Saturday snow amounts become light, and taper off by noon. Winds 10-20 from the NW.

Avalanche Summary

Skier triggered (controlled) produced slab avalanches up to size 1.5. on NW-NE aspects. Northerly aspects continue to load with moderate-strong West winds. Explosive control produced avalanches up to size 1.5 on NW-NE aspects @1800-2200m, slab depths 10-40cm. I suspect there will be an increase in avalanche activity with the forecast wind and snow.

Snowpack Summary

New snow over the past few days have buried a variety of old snow surfaces. These old surfaces are now 30-45cm down and include crusts that exist on all aspects at lower elevations and on steep solar aspects higher up. Facets (sugary snow crystals) and spotty surface hoar (feathery snow crystals) may also exist in combination with crusts, so there may be continued slab reactivity at lower elevations. With more snow and wind in the forecast the new load may have a poor bond to the underlying buried surfaces. Keep an eye on solar aspects Thursday afternoon. Wet, moist snow is a sign of instability. The mid and lower snowpack are strong and well settled. The average treeline snowpack depth is about 240cm.

Régions couvertes