Avalanche forecast

Silver Valley & Bitterroot Mountains

Idaho Panhandle Avalanche Center
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Avalanche danger

Wed
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Out of date — this forecast expired 4 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Buried surface hoar is lurking 8-12" below the surface. Human triggerd avalanches on this layer will be possible at treeline and above today. Sheltered openings at upper elevations in terrain steeper than 35 degrees will be the locations where this potential is highest.  

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2

    The storm that rolled through on Saturday buried a layer of surface hoar approximately 10" below the surface. The distribution and reactivity of this layer is fairly unpredictable. It is often difficult to know where the surface hoar remained intact prior to being buried and this uncertainty should be cause to stay on your toes. The best way to play this game is to assume it is there until you prove otherwise, taking a quick moment to dig through the new snow and look for a thin grey line. Be particularly wary of steep openings where there is enough timber to shelter the snowpack from the winds. These sheltered openings are ideal for growing and preserving surface hoar. (see adjacent photo)

Avalanche Discussion

Yesterday I toured up to Willow Peak with Issy Davis to check out the snowpack and see how our most recent snow was shaping up. As we crested the ridge we were able to view multiple avalanche crowns on Willow peak that appeared to have been triggered by skiers after Saturdays storm. These avalanches released on the previously mentioned surface hoar layer about 10 inches deep. There was also a thin "melt/freeze" crust below the surface hoar that makes for a good bed surface to slide on.  Stability tests were not showing much reactivity in this layer Monday which shows this layer is trending towards gaining strength and healing. Buried surface hoar can be a scary animal however, trying to determine where it was still intact and how reactive it may be is always a challange.

Our deeper weak layer of crust and facets has not showed much reactivity in pits the past week, the facets are rounding and slowly gaining strength in the Silver Valley. The highest chances of triggering this deeper layer will be in steep and open terrain, especially in areas where the snowpack is thin and rocky. Keep this in the back of your mind when choosing terrain as we are getting into a "low-likelihood but high consequence" scenario. If it goes, it will go big and deep.

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