Lawinenlagebericht

Snake River Range

Bridger-Teton Avalanche Center
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Lawinengefahr

Wed
Hochgebirge
4 · Gross
Waldgrenze
3 · Erheblich
Unterhalb
3 · Erheblich
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Veraltet — dieser Lagebericht ist 2 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

Very dangerous avalanche conditions exist. Continued snowfall and wind are stressing a reactive snowpack. You are very likely to trigger an avalanche today on most steep slopes, both in areas where the wind has built drifts and in areas sheltered from the wind. Avalanches can be triggered remotely—from below, above, and to the sides of steeper terrain. Travel in or below avalanche terrain is not recommended today. 

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Very Likely
    Größe
    1–2

    Over the past 24 hours, an additional 6-8 inches of snow have fallen in the Snake. Expect to find touchy wind slabs as new snow will continue to be transported today and tomorrow. Overnight, consistent westerly winds blew in the 10 mph range with gusts to 20s mph, forming slabs 2-3 feet thick terrain above 7,500’. These slabs will be easy to trigger today and create avalanches large enough to bury a person. Additional snowfall and wind this morning will cause these slabs to grow in size and distribution. Natural avalanches are likely in upper-elevation terrain; pay attention to the terrain above you. Extremely careful route-finding is necessary today.

     

    (12/15/2024)

    This large avalanche was remotely triggered in Christmas Tree Bowl in a zone bordering the Snake and with a similar snowpack structure on 12/15 on the surface hoar on the old/new interface. 

  • Storm Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Very Likely
    Größe
    1–2

    All aspects (shaded and sunny) at all elevations are suspect, and only the lowest elevation slopes that were bare ground before have escaped this problem. Slabs could be triggered from a distance or wait until you have committed to the slope to release. The 1.5-2.5' of new snow that has fallen in the past 72 hrs is not sticking well to the old snow surfaces—which consisted of facets, crusts, and surface hoar. Shifting temperatures and time have helped to consolidate the storm snow into a more cohesive slab. Slabs will be thicker, stiffer, and more dangerous in terrain where these two avalanche problems overlap. Any storm slab that releases could break within the newest snowfall, or on the weak snow buried deeper in the snowpack.

     

    (12/15/2024)

    Around 16-20" of new snow has fallen on a weak interface of older snow in the Snake. Observers noted cracking and widespread collapsing. 

Avalanche Discussion

Today is a day to take a few big steps back. Even very experienced backcountry travelers can be taken by surprise in these types of conditions. It can be hard to wrap our heads around the types of avalanches failing during multi-day storms like this one. We find ourselves still amid a large storm with a larger avalanche cycle likely occurring but obscured by poor visibility. More evidence of instability than we think exists, buffed away by the more snow and wind for us never to witness. A second pulse of heavy winds set to hit tomorrow will give this snowpack (and our avalanche eyes) no rest. All steep terrain needs to be looked at with a fresh lens today. This means dialing back slope angles, even in terrain that feels more familiar, & recognizing the consequences of even a small avalanche in that terrain. Avalanches today may break wider than you expect or connect two pieces of steeper terrain with lower-angled features that may appear friendlier but, in fact, are not. 

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