Avalanche forecast

Eastside Region

Eastern Sierra Avalanche Center
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Avalanche danger

Sat
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Out of date — this forecast expired 2 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

You can avoid triggering avalanches by sticking to terrain sheltered from the effects of the wind. You could get into trouble on steep slopes downwind of ridgelines or in gullies, where stiff, textured, rounded drifts might still be sensitive to your weight. The danger will rise as another storm moves in overnight.

Avalanche problems

  • Wind Slabs

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

    Soft slabs that developed yesterday may still be sensitive this morning. They could even grow in size where winds continue to redistribute the recent snow. Expect triggered slabs to be generally small, with the possibility of more dangerous avalanches in favored terrain around the Mammoth area and near the Sierra Crest. There are many shallowly-buried obstacles to get dragged over if you trigger even a small avalanche. Where wind slabs have developed over weak, sugary snow (protected N - E facing terrain), they could break wider and be sensitive for longer. Blowing snow and recent cornices will point to the slopes where you could trigger an avalanche. The leeward sides of ridgelines, alpine couloirs, gully features, and cross-loaded depressions deserve caution. Cracking in stiff, textured surface snow means you’ve found unstable wind slabs. Bigger, more reactive wind slabs will start to form as the next storm ramps up this evening. 

    (12/12/2024) Photo: Eastern Sierra Avalanche Center

Avalanche Discussion

Two to nine inches of new snow and strong winds have built sensitive drifts over the past 24 hours. Forecasters in the Mammoth area—which received the most precipitation—were able to trigger small wind slabs and experienced some cracking underfoot. Snowfall diminished Thursday evening, though ridgetop winds on Mammoth Mountain have remained strong enough to continue building slabs overnight. Fresh drifts have formed over a variety of old surfaces.

Pre-storm, we noted a soft, faceted snowpack on sheltered, shady slopes. Exposed northerlies had wind-board or were covered with a facet/crust combo. Solar aspects and lower elevations had melt-freeze crusts or bare ground. Pre-storm snow coverage, i.e. the sliding surface for today’s avalanches, was most consistent in the Mammoth area and just under the Sierra Crest. You can expect avalanches to be larger and more sensitive in those areas. Limited wind data outside of Mammoth is a source of uncertainty in today’s forecast.

What is more certain is that wind and snowfall should pick up overnight and into Saturday. We are increasingly confident that avalanche conditions will deteriorate quickly after sunset today.

Regions covered