Bulletin d’avalanche

South Columbia

Feb 22 – 23, 2015Avalanche Canada
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Archivé · expiré 12 years ago

Danger d’avalanche

Tue
Wed
Alpin
2 · Modéré
Limite forestière
1 · Faible
Sous la limite
1 · Faible
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Points saillants

Keep an eye on the temperatures on Monday. Solar radiation and rising freezing levels can weaken the snowpack and make destructive avalanches more likely.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–3
    Gusty northwest winds may have redistributed recent accumulations into fresh wind slabs in higher elevation terrain. Warming on Tuesday may reactive these wind slabs and also promote loose wet avalanches on sun-exposed slopes.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely
    Taille
    3–5
    Persistent weak layers have been generally dormant as of late. That said, I'd watch my overhead hazard and be increasingly cautious in steep, unsupported terrain, especially with warming forecast for Monday afternoon.

Confidence

Fair - Timing or intensity of solar radiation is uncertain on Monday

Weather Forecast

The dry ridge will persist throughout the forecast period bringing a mix of sun and cloud until Wednesday. Winds will generally remain light from the northwest, although strong gusts are likely on Tuesday. On Monday we can expect an inversion with above-freezing alpine temperatures. Freezing levels will hover around 1500m on Tuesday, and then drop to about 800m on Wednesday.

Avalanche Summary

Avalanche activity has gradually tapered off throughout the past week, although there has been some wind slab activity to size 1.5 at higher elevations over the weekend in response to northwest to northeast winds redistributing recent snow accumulations. Looking forward, wind slabs may remain sensitive to human triggering, while loose wet avalanches may fail under sunny skies and rising freezing levels on Monday.

Snowpack Summary

Up to 10 cm of recent snow covers the previous variable snow surface of surface hoar, crusts, dry facetted snow, or wind affected snow depending on aspect and elevation. The "Valentine's Day" crust is just below the surface and is now strong and thick in most places. New wind slabs may have formed in lee terrain from recent W-NW winds, and cornices remain large and weak. The late-Jan crust/surface hoar layer (up to 100 cm deep) and the mid-January surface hoar (80-120 cm deep) are generally dormant, and chances of triggering these weaknesses have decreased. However, triggering may be possible with a large input such as cornice fall, or an avalanche stepping down, especially on sun drenched slopes.

Régions couvertes