Bollettino valanghe

Banner Summit

Sawtooth Avalanche Center
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Pericolo valanghe

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2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
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In sintesi

Conditions are tricky right now. Triggering large 1-3’ deep avalanches failing on sugary weak snow is possible in both windy and sheltered terrain. You may not see any signs of danger before triggering a slide. Avalanches could be triggered remotely—from flat terrain below, above, and to the sides of steep slopes.

Problemi valanghivi

  • Persistent Slabs

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

    Triggering a wide, 1-3 foot thick avalanche large enough to bury people remains possible. Soft and hard slabs capable of producing avalanches exist on nearly all slopes, and you'll find facets and/or surface hoar on shadier aspects and crust + facet combinations on sunnier slopes.  

    The odds of triggering a Persistent Slab are slowly decreasing, but the consequences remain severe. Don't expect to see obvious signs of instability, like snowpack cracking or collapsing, before triggering a slide. If you do receive collapsing or cracking, take that as a warning sign and move to lower-angle terrain. You may be able to trigger avalanches from flat or low-angle terrain long distances away from steep slopes.

    Determining whether or not a steep slope will slide once you enter it is nearly impossible right now. The only way to manage this problem continues to be avoiding avalanche terrain, including the base of slopes that are threatened from above. 

    Additional Discussion: Whether a weak layer exists or not, the combination of recent snowfall and moderate to strong winds formed slabs that may remain sensitive to your weight. Watch for dunes, waves, and textured surfaces created by wind.  Feel for stiff slabs overlying weaker or softer snow. These often form near exposed ridgelines. These smaller wind slabs, once moving, are an effective trigger for the larger Persistent Slab avalanches described above.

    (2/26/2026) Snowmobilers remotely triggered this slab avalanche on Thursday, Feb 26th near Bull Trout Lakes in the Banner Summit zone. Note how the crown pulled into very gentle terrain that would not seem dangerous if you were at the top of the slope. NW aspect near 7600'. 

Avalanche Discussion

We’re facing a classic “scary Moderate” scenario. We are just days out from a large avalanche cycle. Slides were remotely triggered on Thursday (1,2). However,  reports of obvious signs of instability, such as cracking and collapsing, have decreased. The likelihood of triggering an avalanche is slowly declining; however, the consequences of being caught in a slide remain ugly.

Three weak layers are buried within the upper 1-3 feet of the snowpack. We’ve seen over 100 avalanches fail on these buried weak layers within the past week. The most likely terrain for similar slides is middle and upper-elevation slopes facing NW–N–NE–E–SE, though SE and W aspects cannot yet be ruled out.

  • On shaded slopes (NW–N–NE–E), you’re most likely to encounter buried surface hoar 1-2 feet deep and/or weak faceted snow 2-2.5 feet deep. The majority of recent avalanches have likely failed on one of these layers.
  • On sunnier slopes (SE and W), crust/facet combinations exist 1–2 feet below the surface and remain capable of producing avalanches.

While overlapping weak layers can seem complex, the overall structure is relatively simple: most slopes harbour the ingredients for slab avalanches, with 1-3 foot thick slabs resting on weak, faceted snow. The only true way to manage low-likelihood/high-consequence scenarios like this is with gentler terrain choices. 

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