Boletín de aludes

Eastside Region

Eastern Sierra Avalanche Center
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Peligro de aludes

Sun
Alta montaña
4 · Fuerte
Límite del bosque
4 · Fuerte
Bajo el límite
4 · Fuerte
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Desactualizado: este boletín caducó 4 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Continued loading by new snow and wind is creating very dangerous avalanche conditions. Large avalanches are expected. Buried weak layers mean you could trigger slabs large enough to kill you from unexpected places, like flat or sheltered areas. Traveling in and under avalanche terrain is not recommended.

Problemas de aludes

  • Wind Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Very Likely
    Tamaño
    2.5–3.5

    Winds shifted from southwest to east overnight and will remain at snow-blowing speeds today. Very large recent wind slabs exist on north and east aspects. Fresher drifts will develop on south and west-facing slopes. You will find these dense, deep, rippled wind deposits on the leeward side of ridgelines and on the sidewalls of gullies. Natural and human-triggered wind slab avalanches are likely to break across starting zones. Avoid travel on or below steep, open slopes, and be skeptical of sheltered areas with wind-loaded avalanche paths above you. 

  • Storm Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Very Likely
    Tamaño
    2

    Increasing snowfall rates and rising temperatures over the past 24 hours have created upside-down soft slabs. Observers easily triggered both slabs and sluffs from low-angled terrain yesterday. Bands of moderate to heavy snowfall today will keep surface instabilities sensitive. You will trigger avalanches breaking in the new snow in steep wind-sheltered terrain. Convexities and confined terrain features deserve particular caution. Avalanches will be most dangerous above terrain traps like cliffs or creek beds. 

    (2/24/2023)

    Intentionally triggered soft storm slab below treeline.

  • Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Likely
    Tamaño
    2.5–3.5

    Well-developed facets and facet crust combos exist 8 to 16 inches underneath the old snow surface. Thick new slabs have developed atop that poor structure. Storm slabs and wind slabs could step down to buried weak layers creating larger, more destructive avalanches. You can trigger avalanches breaking on old snow from below and from terrain you may typically think of as safe. This is a dangerous problem that’s difficult to assess and predict. Avoidance is the best way to manage your uncertainty. 

    (2/20/2023)

    Near surface facets below the old snow surface. NE, 12000', Pine Creek

Avalanche Discussion

Triggered sluffs and soft slabs, shooting cracks, and collapses are common themes from the few observations we received yesterday. As of early this morning, weather stations are reporting up to 2 feet of new snow and almost an inch of snow water equivalent since 6 am yesterday. Gradually rising temperatures likely resulted in upside-down storm snow. Despite less intense snowfall today, already unstable snow will see continued loading. Winds were extreme out of the southwest and shifted to the east overnight. Though they are at more moderate speeds today, that’s still enough to drift snow into slabs on leeward aspects. 

Storm totals of over 4 feet near the Sierra Crest have piled up since the 21st. That intense loading has buried wind and sun crusts, as well as weak faceted layers under thick, dense slabs. Overlapping avalanche concerns, difficult travel conditions, and a complex upper snowpack will prove tricky to navigate. Avoid slopes steep enough to slide if you decide to venture into the backcountry today.

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