Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

Wed
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Out of date — this forecast expired 4 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Strong winds keep blowing snow and building stiff slabs of wind-blown snow near ridges and gullies. People on top of these might cause some of them to break loose and avalanche. Watch out for places that sound or feel hollow or have signs of instability, such as nearby avalanches, snow surface cracking, and blowing snow.

Avalanche problems

  • Wind Slabs

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

    The last several days of wind have hammered the near and above treeline terrain leaving behind variable wind-affected conditions, including unevenly carved snow (sastrugi), scoured icy surfaces, and stiff, smooth slabs of wind-blown snow. The strong NE winds will keep scouring slopes and redistributing snow to new places today. Expect to find dense wind slabs on open slopes near ridges, gullies, and around terrain features like cliffs. Some may even exist in a few spots below treeline. These hard wind slabs may be unstable. Large cornices also still linger above many slopes.

    Hard wind slabs can catch people by surprise since they may not break until someone gets out onto the slab and hits a spot where the slab is thinner or easier to break (trigger point). Identify these potentially unstable areas by watching for places where blowing snow piles up or places where the snow looks smooth and filled in. Look for signs of instability like cracking or unstable test results on small test slopes or on the edges of these slabs where they might be thinner. Route plans that focus on finding terrain sheltered from the wind can help bypass potentially unstable wind slabs and locate more consistent snow conditions. 

    (1/22/2023)

    Wind slab over buried surface hoar cracking in the trees on a N aspect at 9,600', above Horse Meadow, north of Luther Pass, CA.

    Photo: SAC

Avalanche Discussion

  • No new reports of avalanche occurrences were received yesterday.
  • Buried surface hoar - Reactive buried surface hoar was observed again yesterday underneath a wind slab on a N aspect in the backcountry near Heavenly. This was similar to the buried surface hoar seen on both N and SE aspects at 9,600' above Horse Meadow, north of Luther Pass, CA, on 1/22.  Snowpit tests from numerous other locations around the forecast area suggest this layer is unreactive in most locations.
  • Melt-freeze crust exists on the snow surface of many sun-exposed slopes.

Regions covered