Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

Sat
Alpine
4 · High
Treeline
4 · High
Below
4 · High
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Highlights

Despite the storm tapering off, widespread human-triggered avalanche activity remains very likely due to old weak snow below the storm snow and continued blowing snow. Large avalanches could happen on exposed slopes near and above treeline or in sheltered below treeline terrain, which people often consider safe. Travel in, near, or below avalanche terrain is not recommended. 

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    2–3

    Even though the weaknesses within the storm snow may consolidate quickly as the storm tapers off, persistent weak layers like buried surface hoar (weak feathery snow crystals) and facets (weak sugary snow) still lurk at the base of the storm snow. The storm snow will become more of a slab above these old layers, shifting the storm slab problem to a persistent slab problem. In some cases, weak layers may still lurk below the old snow surface, especially in the eastern and southern parts of the forecast area.  These layers will take extra time to adjust to the new load. Significant uncertainty remains regarding which slopes may have already avalanched and where these weak layers may remain. This uncertainty makes even larger safety margins even more important. 

    People can trigger persistent slab avalanches from a distance while traveling below or next to a slope in lower-angle terrain. They also may not release until a person has committed to a slope. These avalanches can also break much wider than expected and may occur in sheltered terrain that people typically consider "safer." The persistent weak layers may also lurk in more exposed terrain where wind-blown snow has created a much thicker slab. Expect large to very large avalanches several feet deep when these old, weak layers of snow fail. 

    (2/13/2025)

    We triggered this avalanche from flat terrain near the spot Steve is standing about 50-100 ft away from the avalanche on an E-NE facing slope at 7900 ft on Andesite Ridge. 

    Photo: Sierra Avalanche Center

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    1.5–3

    Despite the most intense snowfall coming to an end, blowing snow and some additional new snow today will continue to fill in areas near ridges, in gully features, and on open slopes with slabs of wind-drifted snow. These wind slabs will remain unstable today. Some may even fail on the persistent weak layers mentioned in the persistent slab problem. Many wind slab avalanches could involve enough snow to bury or injure a person, and some may be even larger in heavily wind-loaded areas or if they step down to an older, weak layer. The largest wind slabs will exist in near and above treeline terrain, but wind-stiffened snow could also lurk in some below treeline areas due to the strength of the winds. 

    (1/4/2025)

    Several wind slab avalanches on the East Face of Mt. Judah from earlier this season.

    Photo: Andy Anderson

Avalanche Discussion

Even though natural avalanche activity may have decreased as the storm tapers off, large human-triggered avalanches remain very likely. Significant uncertainty also exists concerning which slopes may or may not have avalanched during the peak of the storm. For these reasons, the avalanche danger will remain HIGH today. Avoid traveling in, near, or below avalanche terrain. If you intend to head out into the backcountry today, here are some things to consider.  Pay very close attention to the terrain you choose to travel in. Stick to low angle, non-avalanche terrain without steeper slopes above or to the side. Use maps and observations to ensure you are not in or even close to the runout zones of any potential avalanche paths. Remember that you don’t have to be on a steep slope to be caught in an avalanche that starts from above you. Small terrain features that may seem benign, such as road cuts or creekbeds, could also be dangerous today. 

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