Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

Wed
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Out of date — this forecast expired 3 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Yesterday's snowfall was heavily focused along the Sierra Crest. That is where most avalanche activity is expected today. Areas of recently wind drifted snow may remain unstable near ridgetop areas. More avalanches failing on old snow weak layers deep in the snowpack remain possible in the eastern portion of the forecast area. Conservative terrain choices are recommended.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1.5–2.5

    Wind direction has been from the SE for the past 24 hours and for most of the recent storm. This has created wind slab distribution patterns slightly different from what occurs with our more typical SW storm winds. New snowfall amounts from the past 24 hours were heavily biased to the Sierra Crest. This is where the more problematic wind slabs are expected today. There is a small chance the wind slabs could fail all the way down at the bottom of the recent storm snow near the melt-freeze crust buried on Jan 31. This would push avalanche size up to D3.

    Look for signs of recently wind-drifted snow such as cornice formations, wind drifts, and snow surface texture. Use these clues to identify slopes of concern and consider avoiding them today, especially along the Sierra Crest.

     

    (2/5/2024)

    Classic spot for a wind slab avalanche with signs of recently wind drifted snow.

    Photo: Sierra Avalanche Center

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–3

    A deep persistent slab avalanche was triggered yesterday. This confirms that the recent storm snow load reactivated relatively weak, faceted (sugary) snow near the bottom of the snowpack on the eastern side of the forecast area. Additional deep persistent slab avalanches remain possible today as the snowpack adjusts to the new snow load. This avalanche problem is limited to areas on the forecast area's eastern side where the snowpack had remained shallower all season. Any deep persistent slab avalanches that are triggered today have the potential to be long running, large, and destructive.

    In classic deep persistent slab fashion, yesterday's avalanche already had several tracks on the slope before the avalanche occurred. This means that things are going to seem stable right up until the moment that they are not. The chances of surviving becoming caught in a very large avalanche are low due to the increased likelihood of deep burial and trauma. The only way to effectively manage this avalanche problem is to patiently wait a few more days for the deeply buried weak layers to finish adjusting to the new snow load. When moving through areas below avalanche terrain, keep in mind that this type of avalanche could be triggered from very low on the slope.

    (2/5/2024)

    A deep persistent slab avalanche was triggered yesterday near Relay Peak, NV. Very few details were shared. The reporting party estimated the crown at 4 to 8 feet deep. The debris overran at least three previous tracks on the slope.

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