Lawinenlagebericht

Tetons

Bridger-Teton Avalanche Center
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Lawinengefahr

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

Kernpunkte

Dangerous avalanche conditions exist and triggering a large avalanche remains likely on many slopes—especially in wind-drifted terrain. Avalanches will fail on a layer of weak snow that is buried 1-3 feet below the snow surface. Skiers and riders should continue to choose low-angle terrain that isn't threatened by steeper slopes above. Avalanches are less likely—but still possible—in more sheltered terrain. 

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Likely
    Größe
    1–2.5

    Strong winds over the past 48 hours have worked the recent snowfall and have since shifted directions to more northerly. This shift will load unexpected areas on ridgelines and cross-slope features. Yesterday, periods of heavy snowfall and strong winds built fresh slabs that were sensitive to the weight of a ride and cracked easily.  These slabs may be less sensitive, however, with plenty of snow available for transport, expect to find fresh slabs in new locations today. Expect to find wind drifts 2-3 feet thick in terrain exposed to the wind throughout the course of the day. These slabs will be easy to trigger today and will create avalanches large enough to bury a person. They will be the largest and most sensitive in upper elevation terrain where winds are strongest and are transporting the most snow.

    Pay attention to the terrain that is above you. On slopes that directly face the sun, slabs are resting on stiff, icy crusts. Any slide you trigger in these areas will pick up speed quickly as it travels downslope. 

     

    (2/21/2023) Photo: Erme Catino

  • Persistent Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–3

    A significant slab has been added to locations that have held weak snow, particularly at lower elevations. With the full avalanche recipe now present at a wider range of locations, we have a complex and variable assessment to make as riders. Triggering an avalanche will be most likely on weak snow recently buried within the top 1-3 feet of the snowpack or on yesterday's snow surface. 

    Go back to the basics: we have a handful of persistent weak layers, and they are getting loaded with new and windblown snow. When you look at it that way, it's clear that the avalanche danger is on the rise, and we need to scale back our terrain choices by choosing lower-angled slopes.

    Low-elevation slopes have far weaker snow. Any slope steep enough to slide, regardless of elevation, should be regarded carefully and is avalanche terrain. Conditions will remain very sensitive particularly as winds shift and load unexpected locations. 

    (2/21/2023)

    This skier intentionally triggered this slope in lower elevation terrain, ~7,800 feet on a NE aspect of Wilson Canyon.

Avalanche Discussion

Teton Considerable

I've heard the above term thrown around a lot over the years, but never played a role in crafting the hazard rating and safety message behind said CONSIDERABLE rating before this season. Let's redefine it back to its basic definition, rather than have it hold the idea of confidence in the face of uncertainty. Human-triggered avalanches remain likely. Not many folks were able to enter the alpine yesterday, nor did many want to.  Evidence is lacking in many forms as to how the newest snowfall will behave at middle and upper elevations, particularly with that wicked north wind toeing in. Evidence is not lacking in lower-elevation terrain with its newly-acquired slab capping a very weak and generally thin snowpack, and multiple reports of natural and skier-triggered avalanches yesterday. The weather is in flux, and change is happening at all elevations currently. The snowpack certainly didn't seem "happy" yesterday, and I don't think it will be much happier today. 

Dial back slope angles, pay attention to the consequences of going for a ride even in smaller, lower-elevation terrain, and avoid all wind-loaded terrain. 

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