Boletín de aludes

Salt River and Wyoming Ranges

Bridger-Teton Avalanche Center
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Peligro de aludes

Thu
Alta montaña
2 · Moderado
Límite del bosque
1 · Débil
Bajo el límite
1 · Débil
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Desactualizado: este boletín caducó 2 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

You could trigger a wind slab avalanche in upper elevation terrain—identify and avoid slopes with evidence of wind drifting. Larger avalanches that fail on weak layers buried 2-4 feet deep are possible and carry high consequences. Continue to evaluate the snowpack you move in—be prepared to move to low-angle terrain if you observe signs of instability.

Problemas de aludes

  • Wind Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1–2

    N-NW winds have been blowing relatively lightly but consistently—including yesterday and overnight. Pockets of wind slab remain possible to trigger at upper elevations, and even if small, could push a rider into unwanted terrain or trigger a larger avalanche. Northerly winds often blow upslope, creating unusual loading patterns and cross-loading. Winds will shift westerly today. Expect to find slabs 1-2 feet deep on the leeward sides of ridges and slopes above 9,000’. These slabs will be most sensitive to the weight of a rider in very steep (>35°) and exposed starting zones. Look for signs of wind loading, including fresh drifts, textured surfaces, and features that may remain soft but appear dune-like and rippled. The best approach is to "identify and avoid." 

  • Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Unlikely
    Tamaño
    1–2

    Weak layers of snow are buried 2-4 feet deep in most mid and upper-elevation locations. The likelihood of triggering an avalanche involving these weak layers slowly decreases, yet remains possible today in very steep terrain. Slopes on the north half of the compass are most suspect. Avalanches involving buried weak layers have been observed as recently as 5 days ago. Thin spots in the slab are the most likely places to impact these layers. Thin spots usually exist around steep, rocky, and wind-blown terrain features. Extra caution is needed around rocky, wind-affected, and unsupported slopes as they are where a human is most likely to impact the weak layers buried below. 

    Significant triggers in the form of groups, snowmobiles, avalanches within the new snow, and falling cornices will increase the odds of impacting these layers. Use safe travel practices to minimize your exposure to this problem. Travel one at a time across steep terrain, use islands of safety when stopped, and communicate with your group members throughout the day.

     

Avalanche Discussion

The knowns:

  • Recent snowfall is being compacted into harder slabs of snow at upper elevations, whereas riding in protected meadows and rolling, low-angle hills remains preserved (and fun).
  • Numerous large avalanches were reported here last week.

The unknowns:

  • How well is the new snow bonding to the old snow surfaces?
  • Will additional observations of avalanche activity show more slides that broke deeper in the snowpack or reveal new surface snow instability patterns to watch out for?
  • Where is weaker snow near the base of the snowpack still a concern? Where is it less of a concern?

Safe travel practices remain important, including good communication, traveling one at a time in avalanche terrain, and checking out the snow before committing to steeper slopes on different aspects. The differences in snowpack here range greatly between the east and west sides of the range, as well as north vs south. Being clued into the snowpack history where you ride can help inform your riding plan for the day and avoid the two problems listed above. In many locations, the snowpack is trending towards more stability. Where the two problems overlap is also where it is most likely to trigger a larger avalanche.  Rocky, unsupported, or wind-stripped, shallow slopes that still hold snow should be avoided. Until the list of "knowns" is longer than the "unknowns," keep tight margins on the terrain you choose to enter, not only about slope steepness but also the shape of that terrain and the depth/structure of snow on its slopes.  

Please consider submitting an observation HERE. Observations allow everyone to gain a better and more complete understanding of conditions. Thank you to everyone who has submitted observations this season!

Regiones cubiertas