Bulletin d’avalanche

Selkirk Mountains

Idaho Panhandle Avalanche Center
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Danger d’avalanche

Sat
Alpin
4 · Fort
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré
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Périmé — ce bulletin a expiré 4 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

The north winds have abated some and left carnage in their wake.  Wind slabs at the highest elevations and ridgetops are very sensitive today and some natural avalanches were witnessed.  Westerly aspects, including SE through NW are your main concern for triggering avalanches today.

Problèmes avalancheux

  • Wind Slabs

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

    It's been hard not to notice the winds from the past few days.  They started on Sunday when the weather blew in from the north and Monday the snow started to accumulate.  That combination has given us very unstable windslabs above treeline on wind exposed slopes.  Because the wind was strong out of the NNE you can expect the deepest and most unstable slopes will be the westerly aspects.  Ben was seeing natural avalanches in the bigger terrain of the East Cabinets on Wednesday.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    2–3

    The Lucky Friday crust is still there and we are still seeing problems with weakness due to faceting crystals above the crust.  This layer is about 2 feet deep now in most places.  In stability tests the weak layer fails with moderate force applied and this tells us that there is still a possibility that a person could trigger this layer.  A possible scenario today would be to trigger a windslab and the weight of that avalanche would trigger the deeper weak layer at the Lucky Friday crust and set into motion a very large avalanche.  Be careful on steeep, convex terrain features particularly where the snowpack looks to be not as deep.

Avalanche Discussion

Well,  I have to admit that I was not brave enough to go out in the elements yesterday when I saw the -12 reading on the Bear Mountain snotel and heard the howling north wind.  I knew it was bad enough to create serious problems if anything were to go wrong.  I have Ben to help me out on days like this because he really loves the outdoors.  He was out in the East Cabinets on Wednesday and down on the Idaho/Montana border just north of the Silver Valley yesterday.  He says the problem with unstable windslabs is widespread across our forecast region.  The cold weather for the next couple of days will allow the instability in the windslabs to persist for a couple more days.  Moderate winds today will continue to scour and harden some snow surfaces and build others.  Cornices will be particularly touchy today.  If you can tune into where the snow is hazardous today you should also be able to tune into where those powder stashes are.  Lower angle trees will be the best bet to find great, safe sliding today.

Régions couvertes