Lawinenlagebericht

Snake River Range

Bridger-Teton Avalanche Center
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Lawinengefahr

Sat
Hochgebirge
2 · Mässig
Waldgrenze
1 · Gering
Unterhalb
1 · Gering
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Veraltet — dieser Lagebericht ist 2 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

New snow and wind will form sensitive wind slabs less than 1 foot deep at upper elevations. Pay attention to signs of wind-loading including the formation of pillows and shooting cracks. It is unlikely you will trigger a large avalanche failing on buried weak layers near the ground. 

 

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–1.5

    Today, wind slabs less than 1 foot deep will form in the upper elevations as a storm system brings 2 to 4 inches of new snow and moderate winds. These slabs will grow throughout the day, and be largest in the afternoon. Weakened snow surfaces have developed over the last two weeks, making any new slab formation sensitive to human triggers. Over the past 72 hours, multiple small wind slabs have failed on this weak snow demonstrating the poor structure on the surface.

    As winds shift from the west to the north, expect to find these slabs along ridgelines, in cross-loaded gullies, and on steep convex rollovers on all aspects. Pay attention to signs of wind-loading including the formations of pillows, textured surfaces, or shooting cracks. Moving to terrain sheltered from the wind will help you avoid this problem. 

    D1 wind slab at 8,500' near Wolf Creek. Human for scale.

    Photo: Bridger-Teton Avalanche Center

  • Persistent Slabs

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

    Triggering a large hard slab avalanche is unlikely. Weak layers of snow buried 2-4 feet deep in the Snake River range are adjusting to the weight of the snowpack.  Instability is most likely to be found in very steep, north-facing terrain. Triggering a large avalanche will be most likely in thin rocky areas where you can impact the weak layers.  Larger triggers, such as groups, snowmobiles, or falling cornices, will increase the odds of impacting these weak layers. 

    (1/16/2025)

    An example of complex terrain in the Snake. Very steep, wind affected slopes where trigger points for a hard slab avalanche could be close to the surface.

    Photo: Bridger-Teton Avalanche Center

Avalanche Discussion

As new snow and winds arrive today, wind slabs will start to develop especially at upper elevations. These slabs will grow throughout the day, becoming the largest in the late afternoon. It will be important to remain watchful for signs of instability all day as new wind loading may not be obvious until later this afternoon. Additionally, the new snow will likely not bond well to the weak surface snow that has developed over the past 2 weeks. Due to this interface, I'd expect these slabs to become more sensitive as the day progresses. Stay alert today, and enjoy the small refresh of snow. 

We are now two weeks out from an observed avalanche failing on a persistent weak layer. Buried weak snow on the ground still exists but has mostly adjusted to the weight of the current snowpack. It will probably take a significant increase in load, like a big storm, to see any activity on this layer, and even that is hard to predict.

Please continue to send us your observations!

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