Bollettino valanghe

Togwotee Pass

Bridger-Teton Avalanche Center
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Pericolo valanghe

Sun
Alta quota
3 · Marcato
Limite del bosco
2 · Moderato
Sotto il limite
Senza grado
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In sintesi

Avalanche conditions remain dangerous. Human-triggered avalanches are likely at upper elevations where recent snowfall and winds have formed wind slabs. Watch for signs of additional loading as new snow and wind arrive mid-morning. Use caution around steep, rocky, and wind-affected slopes where it's possible to trigger large persistent slab avalanche on buried weak layers. 

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–2

    Over the past week, Togwotee has received 14-16" of new snow and experienced periods of sustained southerly winds. The combination of wind and snow has formed widespread wind slabs 1-2 feet thick in exposed upper-elevation terrain. Isolated terrain features could hold slabs up to 3 feet thick. Expect additional loading today as snow begins to fall midmorning and overnight winds continue throughout the day. Avoid wind-loaded terrain where you encounter obvious signs of wind-affected snow such as cracking, stiffened/ textured surfaces, and drifts. Suspect terrain includes exposed ridgelines, rocky areas, and cross-loaded terrain features. 

    As winds transport snow, the added weight can stress buried weak layers causing them to become more sensitive. Triggering a wind slab avalanche has the potential to step down to deeper layers initiating a larger avalanche. Carefully evaluate snowpack depth and watch for terrain traps and gullies. If you encounter signs of unstable snow, consider moving to lower elevation, or more sheltered terrain. 

    (3/14/2024)

    Cracking and textured snow surfaces, a sign of instability, and wind-loaded terrain. 

    Photo: Alex Drinkard

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1.5–2.5

    Triggering a persistent slab avalanche is possible on weak snow buried 2-4 feet deep. The weak, sugary snow exists across all elevations and aspects except middle-elevation southerlies. The most probable areas to trigger a persistent slab avalanche include steep, rocky, and wind-affected slopes on the north half of the compass. These areas contain thin, shallow spots where riders can more easily impact weak layers. Shallower snow is also found east of the continental divide and south towards the Gros Ventre Range. Previous tracks on a slope are not an indicator of stability. Use caution in steep terrain and give yourself a wide margin of error on slopes with high consequences or near terrain traps. Move to low-angle terrain to avoid this problem. 

    The last known persistent slab avalanche occurred on 3/16 in Upper Deception Creek. A wet slab avalanche failing on these persistent weak layers occurred on 3/19 on Breccia.

    (3/8/2024)

    Persistent slab avalanche near the 'K' trail at Togwotee.

    Photo: Cameron Galt

Avalanche Discussion

Multiple poor interfaces exist within the top portion of the snowpack. A facet and crust combination was buried on March 21st and 23rd. Many avalanches were triggered in the Teton zone over the past couple of days failing on the interface between the old and new snow - primarily on northerly aspects. There is a lot of uncertainty within the Togwotee zone regarding this interface. While there hasn't been a reported avalanche on this layer; few observations from Togwotee make it difficult to predict how this new crust layer will behave. We will continue to track this interface and develop a better understanding of how it is behaving within our snowpack. In the meantime, I would assume this layer is guilty until proven innocent. Performing stability tests, even quick hand shears, will be important before committing to steeper slopes. Avalanche danger will increase throughout the day as snow continues to fall and avalanches in upper elevations may be large enough to bury a person. I would consider stepping back until we learn more information about this layer. Lower angle and southerly slopes should have a nice refresh of soft snow to play on today. 

If you have read this far, consider taking a moment to help us improve avalanche forecasts! CLICK HERE to take an avalanche forecast survey and be entered into a prize drawing. 

The Colorado Avalanche Information Center, the Avalanche Research Program at Simon Fraser University, and the U.S. National Science Foundation National Center for Atmospheric Research are researching how skiers, snowmobilers, snowshoers, ice climbers, and anyone else who travels in the backcountry interpret avalanche forecast information. Part of this research includes a specific survey to better understand how useful avalanche forecast information is for trip planning. 

Completing this survey will take approximately 20 minutes. Thank you for sharing your feedback to help us improve avalanche hazard communication. 

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