Bulletin d’avalanche

South Coast

Apr 21 – 22, 2014Avalanche Canada
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Archivé · expiré 12 years ago

Danger d’avalanche

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

Avalanche danger can rise quickly with afternoon warming and solar radiation. Be aware of changing conditions and overhead hazards.For more insight into spring danger ratings, check out this blog post.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–3
    Strong S-SW winds have formed wind slabs in leeward alpine features.

  • Cornices

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    2–4
    Large cornices may become reactive during periods of sun and warming.  Cornice falls have the potential to trigger deep instabilities which could result in large, destructive avalanches.

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2
    Loose wet activity can be expected from steep features during periods of solar warming or rain.  Isolated wet slabs may be possible under the same conditions where the recent storm snow is poorly bonded to the underlying crust.

Confidence

Fair - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

Unsettled spring conditions are expected for Tuesday and Wednesday.  A Pacific frontal system is expected to reach the south coast on Thursday. Tuesday: Mostly cloudy, scattered precipitation 2-5mm, freezing level am: 1500m pm: 1300m, ridgetop wind: light S-SWWednesday: A mix of sun and cloud, scattered precipitation 1-3mm, freezing level am: 1000m pm: 1600m, ridgetop wind: light SW-WThursday:  Precipitation 5-10mm, freezing level am: 1500m pm: 1800m, ridgetop wind: light SE-SW

Avalanche Summary

No new avalanches reported.  We are no longer receiving professional field reports from this region so public observations are really appreciated. If you are out in the mountains, please send your observations to [email protected].

Snowpack Summary

A highly variable spring snowpack exists across the region and conditions can change rapidly throughout the day. At lower elevations below-treeline, the snowpack is isothermal and melting rapidly. At mid elevations, between roughly 1500 and 2000m (and higher on sunny slopes), the snowpack is undergoing daily melt-freeze cycles. In the mornings, a refrozen surface generally means good stability. In the afternoon when the surface melts, the stability can deteriorate quickly, especially on sunny slopes. The recent storm has produced dry snow in the alpine resulting in the formation of storm slabs and wind slabs which sit on an old crust. The stability of these slabs has generally been improving but on the first really sunny day, stability is expected to deteriorate rapidly and natural avalanche activity is likely, especially on sunny slopes. Large cornices remain a concern and are expected to become reactive during periods of solar warming. The early-Feb facet/crust layer (down ~2m) and a weak basal layer are both dormant but remain a concern during periods of intense warming, especially in thinner snowpack areas, when large spring avalanches may step down to these layers.

Régions couvertes