Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

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

On E-SE-S-SW-W aspects steeper than 35 degrees MODERATE avalanche danger will form as the day warms up. Some pockets of MODERATE avalanche danger may also form on NW-N-NE aspects that receive sunshine today.

Loose wet snow avalanches will be possible today. Larger wet slab avalanches remain unlikely, but isolated wet slab avalanches will not be impossible as the day warms up.

Avalanche problems

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    Even though temperatures remained above freezing below 9000 ft. last night, clear skies should have allowed a marginal refreeze to occur.  Today's intense sunshine and very warm temperatures will quickly melt through this refreeze. More widespread loose wet snow instabilities like roller balls, pinwheels, and wet point release avalanches should become possible today. Most of these loose wet avalanches should remain too small to bury a person, but they could still push a person into an area with other consequences or could become more serious in areas where terrain traps exist. Loose wet avalanches will be most prevalent on the E-SE-S-SW-W aspects but could also occur on any slope that receives sun including the northerly aspects today.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    2

    Larger wet slab avalanches should still remain unlikely today. However, they are not impossible on the most sun exposed slopes. E-SE-S-SW-W aspects hold the best potential for this unlikely problem, but northerly aspects where sunshine and warm temperatures cause significant wet snow to form could also hold an unlikely but not impossible isolated wet slab. These kind of avalanches are very difficult to predict and confidence in whether or not they could occur today is low. This uncertainty means that wet slabs deserve thought and caution whenever there is a chance they could become a problem.

    Surface wet snow instabilities like the pinwheels and roller balls mentioned above and simple observations such as sinking into wet snow above your boot tops indicate that enough wet snow exists for larger wet snow instabilities like wet slabs or larger wet loose avalanches to occur.  Seeing these things means it is time to find a colder slope or get off the snow and find another activity for the afternoon.

Avalanche Discussion

Yesterday wet snow existed on almost all slopes in the Castle Peak area. Only the shaded northerly aspects above 8600 ft. still held patches of soft cold snow. Roller balls and small wet point releases occurred near exposed rocks on steep SW facing aspects, and ski cuts on steep SE-S facing test slopes triggered pinwheels and wet snow sluffs. Runnels in the snow surface on most aspects, increased water output, and water dripping from cornices all indicated significant warming and melting in the snowpack yesterday. Wet avalanche activity was reported on a NE facing near treeline slope in the Crater Lake area yesterday. This slide started with a depth of about 1 ft. and entrained more snow and got wider as it ran down slope.

Regions covered