Lawinenlagebericht

Snake River Range

Bridger-Teton Avalanche Center
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Lawinengefahr

Sun
Hochgebirge
3 · Erheblich
Waldgrenze
3 · Erheblich
Unterhalb
2 · Mässig
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Kernpunkte

Dangerous avalanche conditions exist. Recent strong winds and snowfall have formed slabs and added stress to buried persistent weak layers. Triggering an avalanche is most likely on steep sheltered slopes or in wind affected terrain. Avalanches could be triggered remotely  on steep slopes above or around you. Evaluate the snowpack carefully and be conservative around steep terrain.

Lawinenprobleme

  • Persistent Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Likely
    Größe
    1.5–2.5

    Triggering an avalanche up to 3 feet deep is possible on buried weak layers. Sheltered, northerly aspects between 8,000’ and 9,500’ are the most dangerous and where we continue to see avalanche activity. Buried facets and surface hoar have a similar distribution in these areas, but dig down to assess where these layers are buried. Buried surface hoar is notorious for wide propagation and being remotely triggered from gentle terrain above, below, or beside steep slopes. Give yourself a wide margin of safety around steep shady slopes today.

    Slopes that are wind-loaded and harbor buried weak layers will be the most dangerous today. These two problems can overlap mostly above 9000 feet on shady and leeward slopes.

    Remotely triggered avalanche from the adjacent ridgeline that failed 5 days ago on buried surface hoar. 

    Photo: Bridger-Teton Avalanche Center

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–2

    Strong west and southwest winds this week have redistributed recent snow and formed wind slabs up to 2 feet deep. These slabs could be sensitive to the weight of a rider. Look for wind slab below ridgelines, around cliffs, and in cross-loaded terrain features above 8500 feet. On very exposed upper elevation slopes, hard wind slabs exist and could break above you instead of at your feet. Look for obvious signs of wind-affected snow, including large drifts, stiffened surfaces, and shooting cracks. Wind slabs could step down to buried weak layers resulting in large avalanches.

    Watch for shooting cracks or signs of wind loading on leeward terain today. 

    Photo: Bridger-Teton Avalanche Center

Avalanche Discussion

Skies are forecast to clear this afternoon, and the sun could make a strong appearance. If this happens, monitor for heating snow surfaces and loose snow shedding on steep slopes facing the sun.  Look for rollerballs originating near steep rocky outcrops and be mindful of overhead hazard. Loose snow avalanches could entrain more snow than you expect.

Surface hoar seems to be the leading culprit for recent avalanches as the snowpack continues to adjust to recent loading. That said, if you find buried surface hoar or faceted snow formed during the January drought on steep slopes, it’s a red flag. Dig around in the top 2-3 feet of the snowpack and see what you find, and if the slab overlying these weak layers wants to propagate (ECTs). Then let us know what you find and send in an observation. It’s critical to our forecasting, and we can’t thank you enough.

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