Bulletin d’avalanche

Northwest Coastal

Dec 29 – 30, 2014Avalanche Canada
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Archivé · expiré 12 years ago

Danger d’avalanche

Wed
Thu
Alpin
3 · Marqué
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Points saillants

Watch for fresh sensitive wind slabs in exposed terrain at and above treeline.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–3
    Reverse wind loading driven by strong outflow winds is forming fresh sensitive wind slabs on lee features.  Be alert for breakable, drummy or punchy snow conditions which may indicate wind slabs.

Confidence

Fair

Weather Forecast

Synopsis: Arctic air to dominate for a few days, then warming from the north. Outflow winds should reach their peak Monday night. By Tuesday afternoon warmer Pacific air associated with the offshore upper ridge should move inland opening the door to a potential inversion or an above freezing layer between 1000 & 2500m.Tuesday: Freezing Level: Valley Bottom; Precipitation: Nil; Wind: Treeline: Light, W/NW | Ridgetop: Strong, W/NW.Wednesday: Freezing Level: Valley Bottom, potential AFL 1000 2500m; Precipitation: Nil; Wind: Treeline: Light, NW | Ridgetop: Strong, NW.Thursday: Freezing Level: 800m, potential AFL 1000 1500m; Precipitation: 3-10mm | 3-10cm; Wind: Treeline: Moderate W/SW | Ridgetop: Extreme, W

Avalanche Summary

Over the last few days we've had reports of naturally and skier-triggered size 1-2 slabs, mostly wind slabs on lee slopes at treeline and above. Explosive control with a cornice drop on Saturday produced a size 2.5 storm slab on a north-facing slope at 1400 m.

Snowpack Summary

Up to 30 cm of new snow from Friday night is being formed into new wind slabs on lee aspects as the winds shift into an outflow pattern. The mid and lower snowpack are generally well-settled. Several old crust layers exist but these appear to be well bonded.

Régions couvertes