Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

Mon
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Stronger wind and more snow than predicted yesterday have left slabs of wind-blown snow on slopes near ridges and in gullies. Triggering an avalanche remains possible where wind-drifted snow has piled up. Traveling in places sheltered from the wind can help reduce the risk of finding unstable areas of wind-blown snow.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2

    Yesterday's much stronger than forecasted gale-force ENE winds led to more significant and widespread wind slab formation. These winds continued through the night and piled any remaining soft snow onto leeward slopes. People could trigger wind slab avalanches on slopes loaded by these winds today. Some wind slabs will quickly decrease in size downwind of where they form. Others could involve enough snow to bury a person, especially in places with the most efficient wind loading or where more snow fell than forecasted yesterday, like the Carson and Ebbetts Pass areas. The largest wind slabs should exist near and above treeline on SE-S-SW-W-NW-N aspects, but some may lurk in lower elevation areas or on other aspects due to the strength of the winds.

    Cornices above a slope, blowing snow, smooth, filled-in-looking areas, and other wind-created surface textures can help identify where wind slabs exist. Recent avalanches, cracks in the snow, unstable test results, or even feeling soft snow below dense wind-pressed snow indicate that those slabs remain unstable. Terrain sheltered from the wind will hold softer, smoother snow surfaces. Plans seeking out this sheltered terrain can help bypass potentially unstable wind slabs and the wind-hammered snow surfaces around them.

    (2/11/2023)

    Human-triggered D1 wind slab on Relay Peak. This slide had a crown of less than 1 ft in depth.

    Photo: Public

Avalanche Discussion

Recent Observations:

  • A party on Relay Peak triggered a small, human-triggered wind slab avalanche yesterday. Skier-triggered cracking occurred on wind-loaded test slopes near Donner Summit. Several parties reported gale-force winds accompanied by plumes of blowing snow across the forecast area. Widespread uneven wind-affected snow surfaces exist on slopes exposed to the winds and ridges. Expect a mix of sastrugi, wind-sculpted snow, wind-pressed snow, and wind-scoured snow in these areas.
  • A snowmobile avalanche class at Blue Lakes reported 8 to 12 inches of fresh storm snow in that area yesterday. 
  • Soft winter snow can still be found on shaded northerly aspects in wind-protected below-treeline terrain.
  • Melt-freeze crusts exist just below the soft new snow on many sun-exposed slopes. 
  • Below the surface, older weak layers still exist (buried surface hoar, near-surface facets, and a graupel layer) in some areas. Over the last several days, observations have shown better bonding and strength in these layers.

Regions covered