Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

Sat
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

Warmer weather and intense spring sunshine should provide enough warming for the possibility of sluffs of wet loose snow today especially on sunny slopes sheltered from the NE winds. Some isolated upper elevation areas in complex or extreme terrain may still hold difficult but not impossible to trigger hard slabs of wind drifted snow. The avalanche danger is MODERATE today.

Avalanche problems

  • Loose Wet

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

    Cool NE winds will work to keep the snow surfaces frozen today while the strong March sun and daytime highs above freezing work to melt the snow surfaces. Whether or not wet snow instabilities form on a slope will depend on which of these has more of an influence. In upper elevation areas exposed to the cool NE winds, less warming will occur and wet snow instabilities should remain limited. In lower elevation areas with less NE wind and warmer temperatures, more warming will mean wet snow instabilities like pinwheels, rollerballs, or sluffs of loose wet snow may be possible. 

    Pay attention to the weather and snow conditions as you travel and be willing to change plans as conditions change. If you are in a sunny area and start to see signs of wet snow like rollerballs, pinwheels, or wet sticky snow, move to a colder aspect where the snow remains cold and dry or switch to lower angle slopes.

  • Wind Slabs

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

    Some hard slabs of wind drifted snow still linger on slopes loaded by the intense NE winds. Triggering one of these hard wind slabs has become unlikely in most places. Still, some instability is not impossible on an isolated terrain feature, especially where the hard slab is thinner or in more complex terrain like couloirs, hanging snowfields, cliffy areas, unsupported slopes, and steep convex rollovers. These hard slabs mostly formed on the NW-W-SW-S-SE aspects in near and above treeline terrain.

    Smooth areas of drifted snow, firm hollow-sounding snow, ripples on the snow surface, and other wind-created features can all help identify where these hard wind slabs may exist. 

Avalanche Discussion

* Hard wind slabs that vary in thickness from a few inches up to 2+ ft exist on slopes loaded by the NE winds. Some of these exhibited signs of instability like whumpfing, cracking, and unstable snowpit tests on Wednesday while others showed no signs of instability.

* Wind scoured and sculpted surfaces are widespread across the forecast area. N-NE-E aspects are especially scoured. Wind-affected snow surfaces exist at all elevations and in traditionally sheltered areas. Some soft snow still exists in the most sheltered areas. 

* Melt-freeze crusts exist on sun-exposed E-SE-S-SW-W aspects. These vary greatly in thickness and strength.

Regions covered