Lawinenlagebericht

Togwotee Pass

Bridger-Teton Avalanche Center
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Lawinengefahr

Mon
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

The weekend storm has brought a combination of new snow and wind that is loading slopes. This weather pattern forms wind slabs and this hazard is expected to continue to grow today. Avoid areas that have been loaded by the wind and limit your exposure to terrain traps. 

Lawinenprobleme

  • Wind Slabs

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

    Snow totals in the Togwotee region from the last 24 hours are generally showing 5 new inches. Wind has accompanied this precipitation and will continue today. This weather pattern builds wind slabs that could be around a foot deep. These wind slabs sit on old, firmer snow that make for great sliding surfaces. We expect to see wind slabs below summits and ridges on leeward slopes. They can also be found mid slope due to cross loading, often catching folks by surprise. Keep an eye out for blowing snow and note where it is getting deposited. Wind slabs often look “pillowy” and can be easily assessed by simple tests like hand shears. These avalanches are especially treacherous when they carry you into or over something hazardous. Monitor your exposure and be careful skiing or riding above features like cliffs or terrain traps.

    Shooting cracks are an obvious sign of unstable snow on the surface.

    Photo: Travis Baldwin

  • Persistent Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    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. On 3/19, a wet slab avalanche failing on these persistent weak layers occurred on Breccia. More avalanches such as these will likely occur today, and many problems may span the border between a wet slab and a persistent slab problem. However, both will be equally destructive avalanche types.

    Weak layers in the Togwotee snowpack are made up of faceted snow grains, like those pictured above. These well-developed facets were found on a NE aspect at 10,000 feet.

    Photo: Cameron Galt

Avalanche Discussion

The weather this weekend continues to be stormy with ongoing light snowfall. Despite relatively small amounts of accumulation, avalanche hazards are present and actively forming on the surface. This time of year sunny spells form widespread crusts that do not bond well to new snow. We currently have this formula, new snow is falling on firm surfaces. While wind slabs are expected at upper elevations, they may also exist below 9,000 ft. 

In addition to wind slabs that sit on the surface, the Togwotee snowpack continues to have weak snow at the base. This problem is most likely to be triggered in thin, rocky spots where the snowpack is shallowest. There is always a potential for a wind slab to step down and trigger a larger, more destructive slide when you have this type of snowpack. Keep an eye out for wind transported snow, stay off slopes that have signs of loading, and choose terrain carefully.

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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