Bollettino valanghe

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Sawtooth Avalanche Center
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Pericolo valanghe

Sat
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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In sintesi

You're most likely to trigger a large avalanche in windier upper elevations and on shadier slopes that face away from the afternoon sun. You may be able to trigger slides remotely—from flat terrain below, above, and to the sides of steep slopes. Sun-warmed slopes may release small wet avalanches in very steep, rocky terrain. 

Problemi valanghivi

  • Persistent Slabs

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

    Dense 2-3' thick slabs overlie weak layers, including sugary facets, surface hoar, and crust + facet combinations on many NW-N-NE-E aspects. Similar but spottier weak layers also exist on the margins of sunnier aspects.

    Persistent slab problems can be tricky to deal with. Don't count on obvious signs of instability like snowpack cracking or collapsing to indicate an unstable slope. Your first sign of instability may be the avalanche you trigger. Persistent slabs may be triggered remotely—from above, below, and to the sides of steep slopes. 

    Simply avoiding avalanche terrain where these slabs + weak layers exist is the best way to stack the odds in your favor. 

  • Wind Slabs

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

    Wednesday and Thursday's quick-hitting storm built 1-2' thick drifts and slabs at upper elevations. Shifting wind directions mean slabs may be found on a variety of aspects, and some may extend down into windier middle elevation terrain.  

    Look for this problem near and just below exposed ridgelines and along cross-loaded mid-slope gullies. Recent cornice growth, pillows, and dunes are all clues that wind was at work moving snow.  Cracking and collapsing are sure indications that you've found a sensitive slab. You can reduce your odds of triggering a wind slab by sticking to more wind-sheltered slopes with soft powder at the surface. 

    Additional Discussion: Today's sun and warm temperatures may initiate small, wet loose avalanches on slopes facing the sun. These are most likely in very steep, rocky, and wind-sheltered terrain. They will begin small but may quickly gain mass and speed as they move downhill over slick crusts. Roller balls or pinwheels are clues that the snow surface is heating up, and loose avalanches may follow. 

    (2/25/2026) A pair of large natural avalanches on a NE aspect at 8800' along the ridgeline between the two Copper Mountain summits. Clear evidence of wind loading and cornice growth is obvious in this photo as well. 

    Photo: Sawtooth Avalanche Center

Avalanche Discussion

Today's avalanche concerns fall into two buckets—"new snow" and "old snow". 

New Snow: These include wind slabs and wet loose avalanches. These are the most likely problems you'll encounter today, but they are also smaller and more manageable. To manage wind slabs, identify and avoid steep wind-loaded slopes. To manage wet loose, monitor the snow surface. Is it getting wet and sticky? Are there roller balls or small sluffs? If so, avoid traveling on or under similar, sunny, wind-protected terrain. 

Old Snow: In this bucket, we have the lingering, persistent slab problem. While less likely to encounter, these avalanches will be much larger and, unlike "new snow" problems, cannot be managed by slope-scale terrain choices. Due to the variable distribution and character of both the slabs and weak layers, stability can change quickly over short distances. Digging a pit is a great way to add a small piece of the puzzle, but don't lose sight of the big picture. Yesterday, our snowpack tests did not indicate instability, but using a single pit to justify big terrain is a mistake. The poor structure (slab over a weak layer) was present not only in our pit but across the entire forecast area. 

Entering avalanche terrain on shadier slopes remains a roll of the dice. Our best and only tool to reliably reduce our risk is to limit our exposure to steep, consequential terrain that faces NW-N-NE-E. 

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