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

MODERATE avalanche danger will exist at all elevations and on all aspects on slopes 37 degrees and steeper. Human triggered loose wet avalanches remain possible today. Some wet slab avalanches may also become possible on isolated terrain features where wet snow exists above an impermeable bed surface. Since most of the snow has melted away from the SE-S-SW-W aspects, wet snow instabilities on these aspects will remain limited to the isolated slopes that still have snow cover.

Avalanche problems

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    Last night temperatures cooled a few degrees compared to previous nights and dipped into the mid to upper 30's above 8000 ft. and upper 30's and low 40's below 8000 ft. These still above freezing temps and the more consistent blanket of cloud cover last night should have prevented the snowpack from undergoing much of a refreeze in most areas. Some places may have experienced a weak refreeze in areas where pockets of colder air existed. Since the cloud cover should start to dissipate today and temperatures should rise into the upper 40's again, any refreeze that did form last night should quickly melt leaving wet snow in any areas where snow exists. Human triggered loose wet avalanches will remain possible today on all aspects on slopes 37 degrees and steeper.

    Since most of the snow has melted away from the SE-S-SW-W aspects, wet snow instabilities will remain confined to the isolated areas where snow cover exists on these aspects. NW-N-NE-E aspects hold the best chances for finding wet snow instabilities today since snow cover remains more consistent on those aspects. Even though these kind of avalanches may not involve enough snow to bury a person, they can push people into areas that would have serious consequences. Keep in mind that secondary terrain hazards such as cliffs and terrain traps hold the potential to greatly magnify consequences of an avalanche that would otherwise be too small to bury or injure a person.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    2

    Wet slab avalanches still remain unlikely in most places, but 4 nights in a row without a solid refreeze, another day of warm weather, and deep wet snow on all aspects where snow exists means that wet slab avalanches may become possible on isolated terrain features. Since the snowpack has already been through so many melt-freeze cycles this year, the potential for these kind of avalanches should remain confined to isolated areas where the most wet snow exists and where a good bed surface (like a granite slab) exists below the wet snow. Use clues like shin deep wet snow and loose wet snow instabilities to help decide when to leave the snow and head for other activities.

Avalanche Discussion

Yesterday observations on Relay Peak showed variable wet snow and melt-freeze conditions on all aspects. Some E-SE aspects held corn conditions with a few inches of wet melt-freeze snow resting on top of a barely supportable melt-freeze crust with more wet snow below it. 10 to 18 inches of unsupportable wet snow existed on other E-SE aspects. N-NE aspects held 10 to 20 inches of wet sticky snow that has not transitioned to corn with old well bonded snow below it. Human triggered pinwheels up to 18-20 inches in diameter occurred on N-NE facing test slopes up to 9800 ft. One small skier triggered collapse about 3-4 ft. in diameter occurred on a low angle S facing slope at 9100 ft.

Regions covered