Bollettino valanghe

Eastside Region

Eastern Sierra Avalanche Center
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Pericolo valanghe

Fri
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato
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In sintesi

Triggering a large avalanche will be more likely as you gain elevation, especially in wind-loaded terrain. Recent avalanches, collapsing, and shooting cracks are all indicators of hazardous conditions. Use conservative terrain choice to limit your exposure and back off from steep terrain if you observe signs of instability.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    Reports of shooting cracks and triggered avalanches in wind-loaded terrain came from the Mammoth and June areas yesterday afternoon. Obvious wind loading occurred across the zone at least through yesterday evening. While it's more likely to encounter these avalanches as you gain elevation, isolated instabilities may exist below treeline in places exposed to the wind. Recent natural avalanches, collapsing and shooting cracks in wind-blown snow, are the most obvious signs of instability. Seek low-angled terrain and avoid steep slopes with drifted snow.

    (2/10/2026) Photo: Clancy Nelson

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1.5–2.5

    Beneath our recent snowfall, multiple layers of weak, faceted snow exist, and an avalanche may release on a buried weak layer. Triggering a large avalanche is likely if you're travelling on or connected to steep north-facing slopes. Remotely triggered avalanches are not impossible. Avalanches may break wider and run farther than you might expect. Signs of instability, like shooting cracks and collapses, may be unreliable. The best course of action is to avoid steep, north-facing terrain with evidence of recent wind deposition.

    (2/8/2026)

    Old persistent slab avalanche on northerly terrain off Royce Peak. This slide likely ran during the 1/4-1/5 cycle.

    Photo: Sean Smollen

Avalanche Discussion

After a month of benign weather and lasting high pressure, northerly slopes faceted near the surface, as well as above and below a crust leftover from New Year's. A few observations also noted weak snow from before 12/24 at the very base of our snowpack. Thats at least 3 well-recorded, complicated, weak layers now buried within our snowpack under a fresh slab.

It is likely that the layer of concern for the persistent problem varies across our forecast zone. In the Mammoth to June Lake area, and closer to the crest, the weak faceted snow directly beneath our most recent snowfall is likely the primary persistent weak layer. The New Year's crust (and the faceting around it) is over 3 feet deep, and a person is unlikely to affect the deeper-buried weak layer.  South of Mammoth and north of June, the likelihood of a persistent slab avalanche breaking deeper in the snowpack bumps up. The snowpack in these areas prior to 2/10 was much shallower and generally composed entirely of facets and crusts.

We have been tracking the development of these interfaces all season, and with the recent slab development, we now have all the ingredients in place. We have received reports of a few intentional and unintentional avalanches on northerly slopes near and above treeline. Some of these avalanches broke wide and had a "hard-to-predict" nature to them. The setup for persistent slabs is out there, and this problem is unlikely to disappear overnight. It is time for a big mindset shift. 

Today and this weekend, build in significant safety margins to your tour plans. Apply conservative terrain choices and careful route-finding to limit your exposure. Ski one at a time and regroup in places out of harm's way. Bring a cautious mindset and tread with care. With sunny skies and fresh snow, the draw to steep slopes will be palpable, and it will be necessary to fight the urge to step out. Over the next few days, success will be measured by a safe return home from a mountain adventure. 

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