Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

Tue
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Out of date — this forecast expired 3 years ago.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

New snow with strong winds will form slabs of wind-blown snow along ridges, gully features, and exposed areas.  New storm snow may not bond well to itself or the old snow surface causing unstable storm slabs.  Make a plan that includes cautious route finding and decision making to avoid todays avalanche problems.

Avalanche problems

  • Wind Slabs

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

    New storm snow overnight and additional snow expected today with strong to gale force winds will create blowing snow and wind slab development.  Newly forming wind slabs along with wind slabs building on top of existing weak wind slabs has been occurring overnight.  We have had an active human triggered wind slab avalanche cycle since last Wednesday with many avalanches up to size D2+.  More wind slab avalanches are likely to occur today with natural wind slab avalanches also possible.  New winds slabs will form on more aspects as winds shift from the SW to the W and eventually NW throughout today.   

    Look for blowing snow, slopes below cornices, wind pillows, and snow surface scouring, as clues to where these wind slabs are forming.  Avoid areas below steep wind loaded terrain and terrain below large cornices.

    (4/1/2023)

    Snowmobiler triggered wind slab avalanche on Secrets Bowl, Little Truckee Summit.

    Photo: Public

  • Storm Slabs

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

    Areas that received the higher end of storm snow totals overnight and additional snowfall today could have storm slab instabilities.  The recent storm snow could have problems bonding to itself or to the old snow surface.  Look for cracking in the upper snowpack as you travel in below and near treeline areas.  If you see signs of unstable snow, move to lower angle areas away from steeper avalanche terrain.

Avalanche Discussion

  • Unstable wind slabs continue in some ridgetop areas.  Many human triggered wind slab avalanches have occurred Wednesday-Saturday throughout the forecast region.  Check out our observation page or the Media Gallery below for more information.
  • A large cornice collapse occurred in Ward Canyon on last Friday.
  • Signs of persistent instability on graupel and crust layers across NW-N-NE aspects within the forecast area have become increasingly isolated and difficult to trigger. Triggering an isolated persistent slab avalanche 1.5 to 4+ feet deep in snowpack has become unlikely on a regional scale yet still not impossible.

Regions covered