Boletín de aludes

Eastside Region

Eastern Sierra Avalanche Center
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Peligro de aludes

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

Lo esencial

Our primary concern remains big avalanches breaking on weak layers buried 3 to 6 feet below the surface. Before venturing onto wind-affected slopes, assess for cracking and collapsing in recently formed slabs. Choosing terrain carefully, sticking to low slope angles, and maintaining wide safety margins are the best strategies for managing the avalanche problems.

Problemas de aludes

  • Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    2–3.5

    Persistent Slab avalanches are more sensitive to a person in the southern half of the forecast area and at lower elevations where the slab is thinner (a meter or less). At higher elevations, particularly from Mammoth north, the slab is thicker (~1.5-2 meters), and feedback may be unreliable. A very large avalanche could be the first sign a slope is unstable. A smaller surface avalanche, or the weight of a person in a rocky area with shallower snow cover, could be all that is needed to trigger an unsurvivable avalanche.

    Managing persistent slabs is difficult. They may be triggered remotely—from flatter terrain adjacent to steep slopes and from terrain people usually think of as safe. Persistent slabs often propagate widely and in unpredictable ways. Tracks on a slope do not mean that it’s safe. Shooting cracks and collapses are clear warning signs of the problem. However, feedback is often irregular. The best option is to minimize your exposure to steep terrain on the aspects and elevations with sugary facets buried under stiffer slabs. Use extra caution in rocky, complex terrain, near convexities, and on slopes with inconsistent snow depth.

    (2/16/2025)

    Crown of a large persistent slab avalanche in Rock Creek.

  • Wind Slabs

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

    Strong southwest winds drifted snow near and above treeline yesterday, loading downwind slopes and reloading starting zones that have the persistent slab structure. Expect these drifts to become more difficult to trigger throughout the day. Asses for cracking and collapsing in drifted snow below ridgelines, in gullies, and on steep leeward slopes. You can avoid the problem by choosing wind-sheltered terrain.

    (2/7/2025)

    Soft wind slabs were easy to trigger only after the slope had been undercut by ski tracks.

    Photo: Eastern Sierra Avalanche Center

Avalanche Discussion

Temperatures dropped well below freezing overnight and are forecast to be a few degrees cooler than yesterday. However, with fully sunny skies and light winds, it won't be impossible to see small surface sluffs. Monitor for changing conditions on sunny slopes throughout the day. Wet, sticky snow, rollerballs, and pinwheels can foreshadow larger point-release avalanches.  

Avalanche conditions vary across our diverse forecast area. Variations in the structure of weak layers in the snowpack, and diminishing signs of instability are sources of uncertainty. However, the consequences of an avalanche failing deep in the snowpack are incredibly high. Poor snowpack structure exists throughout the Sierra, and a rider was killed in a persistent slab avalanche in the Tahoe region on Monday, the 17th. ESAC joins SAC in offering our sincerest condolences to the family and community affected by this loss. 

Patience and disciplined terrain choices are the antidotes to an uncertain snowpack. Low slope angles and low-consequence terrain are the best ways to avoid triggering a deadly avalanche.

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