Avalanche forecast

Eastside Region

Eastern Sierra Avalanche Center
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Avalanche danger

Sat
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

While natural activity will be less likely today, it remains possible to trigger a very large avalanche involving the full depth of the snowpack. Recently formed wind slabs may still be reactive to human triggers. When in doubt, choosing travel routes with lower slope angles and without overhead hazard will limit your exposure.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1.5–3

    Managing our persistent slab problem has become more difficult following our most recent storm cycle. In areas with a deeper snowpack (Mammoth – June), signs of instability may be hard to find. Large slope scale collapses and long shooting cracks continue to be reported in areas with more shallow coverage. In either scenario, a resulting avalanche will likely involve the full depth of the snowpack and may be unsurvivable. While triggering a large persistent slab avalanche will be easier in areas with a generally shallow snowpack, shallowly buried rocks, trees, and convex rollovers will act as good trigger points in areas with a deeper snowpack. These avalanches can be triggered remotely from adjacent terrain and may propagate long distances and beyond terrain features that typically contain surface instabilities like storm or wind slabs. Avoiding overhead hazards and sticking to slopes less than 30º can help you manage this problem today. 

    Photo: Steve Mace

    large persistent slab avalanche activity in the June BC

  • Wind Slabs

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

    Wind slabs will range in size and sensitivity today and may be present on all aspects near and above treeline. Winds over the last 48 hrs have moved around the compass rose and are expected to settle out of the north today. Fresh slab formation is not expected to be significant during daylight hours; however, some new slab development should be expected this afternoon, particularly if snow totals outperform the forecast. Blowing snow, recent drifting, and hollow drum-like snow surfaces are all signs that can clue you into nearby wind deposits. Be suspect of terrain features that encourage drifting, such as the leeward sides of ridgelines, alpine couloirs, gully features, and cross-loaded depressions. Keep in mind that even a relatively small avalanche breaking near the surface has the potential to step down to weak layers at the base of the snowpack, creating a much larger and more destructive avalanche. 

    (2/7/2024)

    Skier triggered windslab, June BC

Avalanche Discussion

Spooky Moderate is a term we often use to describe situations like we find ourselves in today: a frightening phase where avalanches are becoming more difficult to trigger, predict, and manage while showing the size potential to destroy a large truck or small house and certainly large enough to bury or kill a person. Adding difficulty to this situation is the variability in snow depth across the forecast area. In areas with a relatively deep snowpack, signs of instability may or may not be present, but if triggered, avalanches are likely to have devastating consequences. Our most recent storm has also expanded the options for backcountry recreation.  It is critical to remember that in many of these “new” areas, this most recent snow has also added the slab to the avalanche picture, where previously low snow coverage had kept us below the threshold for avalanche activity. In these areas, the distribution of our persistent weak layer is more limited. However, signs of instability may be more common, and avalanches may be more easily triggered. Patience is KEY right now; allowing powder fever to get the better of you could be a costly mistake today. Skill alone is not enough to manage this hazard. Extensive evaluation and deliberate terrain choice are crucial. When uncertainty is high, keep it simple and avoid avalanche terrain.

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