Bulletin d’avalanche

Selkirk Mountains

Idaho Panhandle Avalanche Center
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Danger d’avalanche

Wed
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré
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Périmé — ce bulletin a expiré 6 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Warm temperatures and rain over the past 2 days have caused some big changes in the snowpack. Currently, the biggest problem in the snowpack is the result of weight added to the upper portions of the snowpack. The rain has saturated the upper portion of the snowpack and is adding stress and the underlying weak layers. IPAC has received multiple observations of natural and triggered avalanches.  Expect to see these condition change quickly again today as colder temperatures, snow, and wind move into the forecast zones.

Problèmes avalancheux

  • Wet Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–2

    Until the wet snow in the upper portions of the snowpack freezes expect it to be weak and avalanche prone. Currently the wet slab on the surface is sitting on top of weak faceted snow. If you can imagine piling cinderblocks on a pile of sand and then tipping it to 30 degrees, that's sort of what we're looking at near the top of the snowpack.  Colder temperatues will move in this afternoon and begin this change. If the colder temperatures bring heavy snow as well, be aware of new snow avalanche conditions in the near future. 

    For some more insight on the snowpack, check out the observation s tab on the website. There have been some really good snow/avalanche observations recently. Thank you Alex Drinkard for your recently posted observations! Feel free to add to the observations tab and tell us what you see out there!

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–2

     The snowpack is changing quite a bit right now but I anticipate new snow avalnches becoming the primary issue by tomorrow. Once the current surface freezes, it could create a goood slide plane for the arriving new snow. 

Avalanche Discussion

Backcountry Forecast from NWS Missoula issued: 500 AM MST Tue Dec 22 2020 DISCUSSION: Northwest Montana and North Idaho: The Pacific cold front has passed through northwest  Montana and the Idaho panhandle this morning, and is producing gusts of between 60 to 70 mph at ridge top levels. It will remain windy through mid morning, though gradually decreasing behind the front. A secondary front is still anticipated to shift south out of Canada by mid morning. While snow levels currently remain around 5000 to 6000 feet, this secondary front is expected to quickly drop snow levels down to the valley floors. A band of moderate to heavy snow will likely accompany this band, producing roughly 4 to 6 inches of snow through the terrain through early afternoon. Temperatures will steadily drop behind the front with a wind shift to a more northeasterly direction. Snow showers quickly decrease this afternoon. High pressure then begins to build over the region Wednesday, and will likely linger through Friday

Régions couvertes