Bulletin d’avalanche

South Columbia

Apr 3 – 4, 2013Avalanche Canada
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Archivé · expiré 13 years ago

Danger d’avalanche

Fri
Sat
Alpin
1 · Faible
Limite forestière
2 · Modéré
Sous la limite
2 · Modéré
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Points saillants

Be alert to conditions that change with daytime warming. Danger ratings are likely to exceed posted levels if solar radiation is strong, especially at treeline and below.

Problèmes avalancheux

  • Cornices

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    2–6
    Cornice falls are a concern during warming. Slopes with corniced entrances, or exposed to cornice falls should be avoided. It is possible that the weight of a cornice dropping onto the slope below could trigger an avalanche on the Mid-March crust.

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–4
    With little re-freeze overnight, conditions can change rapidly at lower elevations. Avalanche activity, snowballing, moist and wet snow are initial indicators of deterioration and increased hazard.

Confidence

Fair - Freezing levels are uncertain for the entire period

Weather Forecast

Thursday: A weak high pressure system builds promoting clear and dry conditions with light westerly winds and 2000m freezing levels.Friday: An upper trough of low pressure will move over the Interior late Thursday through Friday bringing moderate to locally heavy precipitation. Freezing levels will be around 1400m. Winds light to moderate from the west.Saturday: Overcast with light to locally moderate precipitation possible. Winds light from the south.

Avalanche Summary

Solar aspects have been very active showing lots of natural loose wet avalanches and cornice releases up to size 2.5.

Snowpack Summary

Surface faceting and surface hoar growth ( up to 20 mm) has been prevalent on shady slopes at upper elevations, while the surface snow on sun-exposed slopes and at lower elevations has been subject to daily melt-freeze cycles. Cornices are large and weak.Surface hoar buried March 10th is down 100cm in most places. This layer seems to be bonding in most places and is a low probability - high consequence problem. Triggering may be possible with a very large load (cornice fall) or hitting the sweet spot in thin, variable snowpack areas.

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