Bulletin d’avalanche

Northwest Coastal

Apr 8 – 9, 2019Avalanche Canada
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Archivé · expiré 7 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

South winds have formed wind slabs that rest on a widespread crust. The best riding and highest danger are expected to overlap on high elevation north facing features. Even a brief appearance of the sun may initiate loose wet activity too.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2
    10 to 40 cm of storm snow rests on a widespread crust. Strong southerly winds have likely formed fresh slabs in high elevation north facing features. Human triggering is most likely immediately lee of ridgecrest.

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–1.5
    Some filtered sunshine may initiate a loose wet avalanche cycle in the new snow. The likelihood of loose avalanches increases as temperatures warm through the day and/or if the sun comes out for a prolonged period of time.

Confidence

Moderate -

Weather Forecast

A low pressure centre over the Gulf of Alaska continues to produce weak systems that impact the Northwest Coast. The Tuesday Night system should deliver another round of snow to the alpine, but it is difficult to pin down accurate snowfall amounts at this time, stay tuned for more details.MONDAY NIGHT: Freezing level around 1300 m, light to moderate southwest wind, trace of snow possible.TUESDAY: Overcast, freezing level around 1000 m, moderate west/southwest wind, 1 to 5 cm of snow possible. Another 5 to 10 cm of snow possible on Tuesday Night.WEDNESDAY: Broken cloud cover, freezing level rising to around 1000 m, light southwest wind, 1 to 5 cm of snow.THURSDAY: A few clouds in the morning with potential for clear skies in the afternoon, freezing level climbing to 1500 m, light variable wind, no significant snowfall expected.

Avalanche Summary

We received a great MIN report from the Shames backcountry that describes an active wet loose avalanche cycle to size 1.5, more details here. Wind slab avalanches were susceptible to explosive triggering on Sunday to size 2.5 as well. If you're out we'd love it if you would submit what you're seeing to the Mountain Information Network.

Snowpack Summary

10 to 40 cm of rather wet storm snow now rests on a weak layer buried April 4th which consists of crust, surface hoar and facets. The crust is widespread and up to 4 cm thick. Spotty surface hoar and facets have been reported on top of the crust on high elevation north facing slopes. Moderate to strong wind generally out of the south over the weekend likely formed fresh slabs which may remain sensitive to human triggering. North facing alpine terrain also has a layer of facets down 40 to 100 cm below the surface, but this layer has not been recently active and is likely trending towards dormancy.Below treeline the snowpack is isothermal throughout much of the forecast region.

Régions couvertes