Bollettino valanghe

Silver Valley & Bitterroot Mountains

Idaho Panhandle Avalanche Center
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Pericolo valanghe

Sat
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
Non aggiornato — questo bollettino è scaduto 6 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

We have a multi-layered snowpack with instabilities that are just starting to wake up with the new loading we are receiving. Expect the unexpected. Yesterday's storm added a lot of new snow and winds that blew that snow around. We are expected to get more snow throughout the weekend that will increase the danger.  Overall the snowpack is still shallow, so a big danger is still hidden sharks.  The season is finally starting to show some promise, so dial it back so you can enjoy it for its full length!

Problemi valanghivi

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    We recieved between 9 and 12 inches of new snow yesterday in some locations which might be sitting on a good sliding surface underneath in the form of an ice crust.  As more snow is predicted, expect these slabs to continue to build with high density snow.  

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–2

    At the upper elevations yesterday the winds were moderate to strong and were moving snow around quickly. Snowmobile trenches were completely erased in the couple hour span of being out.  Watch out for windloading on the leeslopes as well as cross loading in gullies.  Look for stiff, hollow sounding snow that is pillow like and chalky.   Shooting cracks are a definite red flag for windloading.  Expect to find sensitive windslabs at the top of any drop in, avoid windloaded start zones greater than 30 degrees.  These windslabs will continue to grow with more snow and wind throughout the weekend.

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    Our snowpack is a layercake of weak layers right now.  If you dig down, expect to find buried surface hoar, melt freeze crusts, rounding snow, graupel, basal facets, and near surface facets.  The ones that we are most worried about are those buried surface hoar layers and the near surface facets.  These are touchy in some spots and unreactive in others. As the new storms build depth and weight over these layers, I expect the reactivity to increase.  Watch for red flags of shooting cracks and woomfing.  Don't be complacent about your investigations, these layers deserve your attention. Dig down and give them a look, perform stability tests before venturing out onto slopes that are avalanche terrain. 

Avalanche Discussion

Our snowpack has a lot of spatial variability right now, both in the layers it is comprised of and the depth of snow we are seeing across our region.  One thing we all need to remember is that it is still early season.  More snow will come, and more problems will come with it.  Now is the time to be conservative, get your legs underneath you for the season, and start paying attention to what the snowpack is telling us.  The buried persistent layers will be with us for a while, so get used to hearing about them in the forecast already!

I can't stress enough that we have a young, weak snowpack with a lot of layers that could potentially wake up with added snow loading. When you are out this weekend enjoying the new snow, make sure to do it in a safe way by choosing low angle terrain.  Added bonus is that low angle terrain has better coverage of those hidden sharks as well!

If you are out an about, we would love for you to submit an observation.  We generate a forecast for a lot of area, but we can't see everything out there. Your snowpack and weather observations help round out the picture of our forecast areas and fill in the gaps. 

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