Lawinenlagebericht

Togwotee Pass

Bridger-Teton Avalanche Center
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Lawinengefahr

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

Kernpunkte

Persistent weak layers buried 1-3 feet deep remain a concern as triggering large, dangerous avalanches are possible. These avalanches are most likely in complex terrain with slopes over 35° steep that are rocky and wind affected. Lookout for wind loaded terrain where persistent slab and smaller wind slab avalanches could be triggered.

Lawinenprobleme

  • Persistent Slabs

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

    Weak snow buried 1-3 feet deep below hard slabs remains a concern. Strong northwest wind over the last 48 hours has loaded slopes and stressed a weak snowpack. Wind loaded slopes in exposed, alpine terrain are where persistent slab avalanches are most likely in the upper elevations today. Slopes over 35° steep that contain thin, sensitive areas in the slab are more likely places to impact buried weak layers. Thin spots usually exist around complex, rocky and, wind-affected terrain. 

    In terrain sheltered from the wind, the odds of triggering a persistent slab avalanche have decreased over time. Unfortunately these weak layers require a long time to heal. Stability tests are still showing unstable results despite the lack of recent avalanches. Remain vigilant traveling through avalanche terrain. Identify complex terrain where avalanches are more likely and look out for terrain traps where unsuspecting slopes can have serious consequences.

    An example of terrain where persistent slab avalanches are most likely.

  • Wind Slabs

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

    Strong west/northwest wind over the last 72 hours has formed shallow wind slabs less than 12 inches deep. These stiff wind slabs have been easy to trigger the last several days as they lie on weak interfaces. Although small, these wind slabs could knock you off your feet or machine. Only a few more inches of snow combined with moderate wind are expected today. Larger slabs will be found above the treeline and more likely off ridgelines or around confined features like couloirs. Seek terrain sheltered from the wind if you encounter signs of instability.

    (1/23/2025)

    Shooting cracks and rippled snow surfaces indicate signs of instability on wind loaded terrain. 

    Photo: Bridger-Teton Avalanche Center

Avalanche Discussion

The Story Persists

Today a quick weather system impacts the forecast zone moving north to south. Only a few inches of snow are expected by the end of the day with west/northwest wind around 20 mph on ridgetops. Old wind slabs along with fresh wind drifted snow lies on weak interfaces formed from the last week of dry conditions. Near surface facets and crusts are scattered across the mountains, providing an easy surface for new snow avalanches to move on. Although small in depth, these avalanches can travel far cross-slope as we’ve seen this week.

Your odds of triggering an avalanche are slowly decreasing, but each day is only incrementally safer than the last.  The recent strong wind event loaded many slopes and has added stress to persistent weak layers in specific areas. This has certainly not helped the snowpack stabilize. Evidence of wind scour and loading of snow was very obvious during field observations this last week. Pay attention to subtle clues in the snow surfaces to identify wind loaded terrain where heightened avalanche conditions exist. Areas in the alpine such as Angle, Breccia, and Bonneville are prime examples of locations where significant wind loading can rapidly stress the weak snowpack. The last reported cycle of persistent slab avalanches occurred January 7th. 

 

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