Boletín de aludes

Togwotee Pass

Bridger-Teton Avalanche Center
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Peligro de aludes

Thu
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

Recent snowfall and several days of wind have increased the chances of triggering an avalanche in upper-elevation terrain. You’re most likely to trigger a slab avalanche in freshly formed wind drifts. Underneath these drifts, weak snow near the bottom of the snowpack continues to pose a threat. To reduce your risk, steer clear of slopes where the wind has stiffened the snow surface.

Problemas de aludes

  • Persistent Slabs

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

    New snow will form sensitive, though small, slabs today. Early-season persistent weak layers in the lower snowpack are widespread throughout this zone. What's less consistent is the nature and stability of these layers. Despite having such a poor overall snowpack structure, it is remarkable how little activity has been noted here. This is likely due to observation bias--so continue to send us your observations! This zone has very weak snow buried 2 to 4 feet deep on most middle and upper-elevation slopes. Digging a pit can easily identify most of these layers, and stepping off of a sled or probing for depth can also help identify weaker snow. Sinking deep into the snowpack on foot is a clear sign of a weaker snowpack. 

    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

Today's forecast order comes with a hefty dose of uncertainty sauce, and you are the chef. If snow and wind totals pan out as predicted in the alpine, I suspect you could buy an avalanche, and hazard will increase throughout the course of the day. If they don't pan out, then expect the overall hazard to be less. The wind is probably one of our least favorite winter weather factors, and lately, it has been the primary force behind our avalanche conditions. In areas where these wind slabs form atop snow surfaces that aren't persistent weak layers, such as softer new snow, older wind slabs, and crusts, the period of instability is often short-lived. Warmer temperatures can help to speed up the process of stabilization. The trouble is that consistent winds over the past several days formed fresh, touchy wind slabs even as old wind slabs stabilized.

The more complex issue with recent wind loading is where the wind slabs are adding additional weight to buried persistent weak layers. Where our snowpack remains shallow and especially weak—for example, the windswept areas of the Greys River and Togwotee—the recent wind loading is more hazardous. This problem is likely to persist longer than the pure wind slab problem and has the ability to produce a much larger avalanche.

Fortunately, areas with recent wind loading are easy to identify with in-the-field, tangible observations. The snow surface on wind-affected slopes usually has a different texture and will be denser and more cohesive than the snow found on sheltered slopes. Keeping your eyes open for these clues (well, keeping them open at all with the predicted winds today), and avoiding steep slopes where you find them, will help you avoid most of the avalanche risk that currently exists in our area. This is especially true if you find yourself in alpine areas or where the snowpack remains on the shallow side. 

So there's your recipe: start with a base knowledge of the snowpack in areas you frequent, add a splash of reading the forecast and adjusting it for incoming weather, sprinkle with the right partners and good communication—and mix all of the above in terrain that fits your assessment. 

 

 

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