Avalanche forecast

Eastside Region

Eastern Sierra Avalanche Center
View on map

Avalanche danger

Mon
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
Open full map
Out of date — this forecast expired 2 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Avalanches are possible at all elevations after a mix of rain, snow, and extreme winds. You’ll be able to trigger the largest avalanches in wind-drifted snow or closer to the Sierra Crest, but still be wary of wet snow at lower elevations. Expect generally challenging and arduous travel conditions.

Avalanche problems

  • Wind Slabs

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

    Close to 12 inches of new snow fell along the Sierra Crest in the past two days. This new snow bonded with consolidating snow from last week's storm—on top of older, faceted snow on E-N-NW aspects. Combined with strong to extreme S winds which will continue into the day, these slabs will be largest in areas where the wind has deposited snow: on the leeward sides of ridges, mid-slope catchment zones on the walls of gullies and below convex rolls. With the amount of rain/snow mix we received, expect these to break in unusual ways, in lower elevation terrain, and wider than expected. These will be largest where there is the most precipitation in the northern part of our forecast area.

    Cracks shooting out from your skis or board are a clear sign you have found a slab.  Surface textures like dunes and drifts indicate the wind has been at work. If the snow you are moving through quickly becomes deeper, stiffer, and more dense, you have found a slab. 

    (12/24/2024)

    Shooting crack in wind stiffened snow

    Photo: Steve Mace

  • Loose Wet

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

    This atmospheric river brought a mix of rain and snow to elevations close to 10,000 feet over the past two days, without a solid refreeze last night. This water saturated the snow from last week's storm, as well as the new snow. Fluctuating temperatures made varying density snow layers throughout this new snow. As surface snow melts and water percolates down to the various crusts from earlier this season, it will become increasingly easy to trigger loose avalanches in this wet snow. These are most likely on steep slopes, will start out small, and can gain speed and size as they run downhill.

    With the amount of new snow during the day yesterday, it is possible for a larger, drier avalanche to gain mass and combine with these wet avalanches at mid-elevations. These slides can be particularly destructive. If the snow surface is wet, then it is a sign that these slides are on the menu. Be on the lookout for rollerballs, pinwheels, or any signs of the snowpack peeling off from lower layers. 

Avalanche Discussion

After a wet, warm, and sloppy Saturday, precipitation tapered off last night for a dry period today to dry out your boots.  The back and forth between rain and snow combined with strong to extreme S wind, has made for a strong over weak structure in the upper third of our snowpack. This system's precipitation has been primarily snow in the northern part of the forecast area, where more precipitation fell, trending toward rain and lower totals to the south over the past two days.  This made for a wet, dense, cake-like layer of new snow ranging from 4-14 inches thick—thicker on leeward aspects from NE-N-NW—bonding to consolidating snow from last week's storm. Below this is weak, old, faceted snow on most E-N-NW aspects. While these slabs have had some time to settle overnight, the amount of new water injected into the snowpack yesterday leaves us with some uncertainty. Without a solid refreeze overnight, this structure, and the amount of free water still in the snowpack, need time to settle and restabilize.

If you choose to head out into the hills today, be prepared not only with the knowledge of a weak snowpack structure, but for generally challenging conditions. The menu: extreme gale force winds, surfaces from breakable crust to bulletproof ice to unconsolidated shmoo that'll have you wondering if you're in the Cascades. If you're up for the adventure today, then I'd recommend many layers, and wide margins in your travel plans.

Regions covered