Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

Sat
Alpine
4 · High
Treeline
4 · High
Below
4 · High
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Highlights

A strong atmospheric river storm will impact our forecast region over the next couple days with heavy rain and high elevation snow.  Large and destructive avalanches that run long distances are expected.  Travel in, near, or below avalanche terrain is not recommended.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    2–3

    Gale force SW winds with gusts well over 100mph over exposed ridges and peaks will continue throughout today.  Large wind slabs will form in near and above treeline areas at the higher elevations above the snow line with some wind slabs also forming in below treeline areas with the intense winds.  Wind slab avalanches could fail and become wet as they run downslope and entrain large amounts of wet snow.  Rain falling on newly formed winds slabs will deteriorate the bonds and strength of these wind slabs, with them failing with wet snow avalanche characteristics.  Widespread avalanche activity is expected throughout today.  Large built out cornices from the previous storm will collapse today due to the extra weight from wet heavy snow or large amounts of rain.

    These avalanche could run long distances into below treeline areas. Travel in or below avalanche terrain is not recommended today.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    1–2.5

    Heavy rain is moving into the forecast region early this morning and will continue through today and tonight.  Rain on new snow will deteriorate bonds and strength of the upper snowpack and cause widespread loose wet avalanche activity.  Small to large loose wet avalanches will be likely in all areas where rain on snow is occurring.  Some of these avalanches could have wet slab characteristics and entrain more deep wet snow as heavy rain continues to weaken the snowpack.

    Travel in avalanche terrain is not recommended today.

Avalanche Discussion

  • Wind slab avalanches were reported yesterday.  Multiple large to very large natural wind slab avalanches occurred at the end of the last storm cycle on Wednesday.
  • Large built out cornices exist on many ridgelines that formed during our last storm event.

Regions covered