Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

Alpine
1 · Low
Treeline
1 · Low
Below
1 · Low
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Out of date — this forecast expired 11 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

LOW avalanche danger continues for all elevations and aspects. The potential exists for the unlikely triggering of small avalanches in isolated areas. Continue to use accepted best practice travel techniques while traveling in or below avalanche terrain. Keep exposure limited to one person at a time and avoid grouping in avalanche run out zones.

Avalanche problems

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    1

    Good snowpack stability exists across much of the forecast area. Isolated pockets of instability remain ongoing mainly near treeline and below treeline on NW-N-NE aspects. In some but not all of these areas, faceted weak layers are found below a slab either at mid height or at the bottom of the snowpack. In areas where this snowpack structure exists, any signs of instability including collapse, whumpfing, or unstable snowpit test results are cause for conservative decision making. The overall snowpack remains less than 2.5 feet deep in most areas so it takes little effort to poke with a pole or intentionally trench a snowmobile across a test slope to have a look for well bonded snow on top of somewhat loose grained facets.

Avalanche Discussion

Recent observations including those made in the Luther Pass, Pole Creek, Mount Rose, Carson Pass, and Donner Summit areas, all point to a fair amount of spacial variability in the snowpack in near treeline and below treeline areas on NW-N-NE aspects. In some areas faceted weak layers exist. In other locations of similar aspect and elevation these weak layers are notably absent. In areas where these weak layers exist, collapsing, whumphing, and unstable snowpit test results have been observed as recently as Friday. In areas where these weak layers are absent, no obvious signs of instability or unstable snowpit test results have been observed. Strong temperature gradients within the snowpack indicate that faceting will continue in the short term.

Above treeline and on the sun exposed E-SE-S-SW-W aspects conditions are very similar across the forecast area. Pockets of wind scouring and wind drifted snow exist above treeline. Evidence of instability above treeline has been limited to very minor human triggered cracking of wind pillows over the past few days. On the sun exposed and wind protected slopes, a very shallow well anchored snowpack exists with the most recent new snow covering either melt-freeze layering or ground level rocks and vegetation.

Regions covered