Boletín de aludes

Togwotee Pass

Bridger-Teton Avalanche Center
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Peligro de aludes

Wed
Alta montaña
2 · Moderado
Límite del bosque
2 · Moderado
Bajo el límite
Sin grado
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Desactualizado: este boletín caducó 4 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Winds over the past week have blown the recent snowfall into slabs and drifts in upper elevation and alpine terrain. Avoid steep slopes where you find wind-drifted or pillowed snow, and areas where the wind has drifted new snowfall onto crusts. Triggering an avalanche on weak layers buried 3+ feet deep remains a possibility on very steep, rocky, wind-affected slopes at middle and upper elevations.

Problemas de aludes

  • Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1–2.5

    New snow will remain more sensitive where it has fallen on a crust on the southern half of the compass. Lingering weak snow also exists deeper in the snowpack, and wind-drifted areas pose a higher hazard for triggering a larger avalanche on one of these layers. This zone has persistent weak layers buried 2 to 4 feet deep on most middle and upper-elevation slopes.  A similar problem exists on the western side of the Tetons, where I found a shallow snowpack and a thick layer of facets from the January 26 storm. Though my pit did not propagate, I suspect an area with a heftier slab would, and finding this structure alone brings pause, and I suspect it will stay with us for a while. 

    Steeper areas you ride that are shallower now may likely prove more hazardous with any large snowfall or wind event, so keeping track of these areas will be useful.  The presence of these layers is the most important observation, and monitoring their activity with any incoming wind and snowfall. 

    WIND SLABS: Watch for snow that is denser than snow found on wind-sheltered slopes and tell-tale clues such as surface texture and a pillowed, drifted appearance. These will be less sensitive today, but I'd still avoid steep slopes where you find these indications of recent wind loading.

    (2/5/2023)

    This recent avalanche failed on weaker snow near the base of the snowpack and shows

    Photo: Dawson Hatch

Avalanche Discussion

State of the Snowpack

The Togwotee snowpack is the shallowest and weakest, especially around the Grouse and Brooks areas. As is not uncommon in this area, there is plenty of weak, faceted snow—what's lacking is a slab of cohesive snow atop it in many spots. Currently, unstable slopes are largely limited to where recent and/or past wind events have created dense or stiff snow in the upper pack. The incoming storm tomorrow will favor the Tetons and Togwotee, so expect to see changing conditions and higher wind speeds.

The Greys River zone is the unpredictable one in the middle. There is a great deal of variability across this zone, but it all falls somewhere between the two scenarios described above. The thin, windswept snowpack of the Salts has characteristics of Togwotee, where wind slabs sitting atop weak, faceted snow are the main concern. The Wyoming and Snake River areas have a bit deeper snowpack, with early-season weak layers buried 2-4 feet deep. In the Salt Range, the faceted snow near the ground seems especially pronounced

The deepest snowpack exists in the Tetons*. I put an asterisk here because the west and east side of the range have entirely different snowpacks, and the west side remains far thinner with a more obvious weak layer development that will persist. Overall, a sandwich of persistent weak layers remains highlighted on the southern half of the compass in the middle and upper elevations. My primary concern is a thicker layer of facets exhibiting a more widespread pattern which was buried in late January. These layers are buried 3+ feet deep due to the nature of the larger storm that buried them. This, to me, reads that triggering an avalanche on them may be more difficult, but likely larger and very consequential. This layer is worth looking for in pits and assessing carefully with recent and changing weather on the way. Avoiding thinner "trigger points" is the name of the game—these are more likely to be found in very steep, rocky, alpine terrain that is prevalent on the west side, but less so on the east.

So there you have it— familiarize yourself with the snowpack in areas you frequent, keep your head on a swivel with incoming weather, know the people you like to get out with and how well you all communicate—and choose terrain that fits your assessment of all of the above. 

 

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