Bollettino valanghe

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Sawtooth Avalanche Center
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Pericolo valanghe

Wed
Alta quota
3 · Marcato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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In sintesi

Natural and human triggered avalanches are most likely in steep terrain where you feel comfortable wearing only a shirt and shorts: sun-drenched slopes sheltered from the wind. You could trigger slab avalanches where you find drifts, wind-stiffened snow, or cornices. Smaller loose snow avalanches could release naturally—on their own—on steep slopes while they directly face the sun. Be prepared to start and end your day early, and don't linger beneath large, rocky avalanche paths facing the southern half of the compass.

Problemi valanghivi

  • Loose Wet

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

    What and where is it?  Natural and human triggered wet loose avalanches are likely on steep, wind-sheltered slopes while they directly face the sun. These slides often initiate near the base of trees, rocks, and cliffs, starting as small point releases and entraining snow and fanning out as they move downhill. The majority of these slides should involve only the recent snowfall, but they can grow large enough to knock you off your feet or sled and carry you where you don't want to go. 

    How do we recognize and manage it? Rollerballs, pinwheels, and wet, slushy snow surfaces are clear signs the snow is heating up; wet avalanches may follow. These slides could trigger larger slab avalanches as they move downhill. Even small slides are surprisingly difficult to escape and are consequential above terrain traps such as gullies, creeks, and trees. Avoid lingering under big avalanche paths and steep, rocky slopes while they directly face the sun. 

    Additional Discussion - Cornices: Cornices could break on their own as they sag during the heat of the day. Natural cornice fall can trigger both wet loose slides and the larger slab avalanches described below. 

    (3/16/2026) This natural wet loose avalanche released mid-day on Monday, March 16th at middle elevations in the Meadow Ck drainage near Williams Peak, Sawtooth Mtns. Note how it "tried" to flank out as a slab avalanche as it moved downslope. 

    Photo: Friends of the SAC Governing Board

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1.5–2

    What and where is it? Several large, 1-2 foot thick avalanches released naturally on Saturday in this and neighboring zones. The last storm formed wind slabs below corniced and exposed ridgelines, on the sides of cross-loaded gullies, and in cirques below steep faces, large cliff bands, and chutes. The slabs are largest and most widespread at upper elevations but also exist in some exposed terrain below 8500'. You could find wind slabs both at ridgelines and lower on slopes than you might expect.  

    How do we recognize and manage it? 

    • Look for smooth snow pillows, dunes, textured snow surfaces, and cornices. 
    • Feel for changing surface conditions. Wind slabs are stiff and can feel or sound hollow or "drummy."

    Fortunately, the wind slabs are fairly easy to identify and avoid. Snowpack cracking and collapsing are clear signs of unstable conditions. Give cornices a wide berth; they can break on their own or with the weight of you or your sled. Falling cornices are great triggers for slab avalanches. 

    Additional Discussion - Persistent Slabs:  Although it would take some bad luck, you could trigger a much larger, 2-4 ft thick persistent slab avalanche on buried weak layers (sugary facets, surface hoar, and crust + facet combinations). Recently wind-loaded, middle and upper elevation slopes facing NW-N-NE-E are most suspect. Don't expect to experience obvious signs of instability; the first clue could be the avalanche you trigger. 

     

    (3/15/2026) Natural avalanche in wind-loaded terrain near Cape Horn Summit. 

Avalanche Discussion

Yesterday's warm temperatures and cloud cover created moist or wet snow surfaces on nearly all slopes (video). Today's intense sunshine and the hottest temperatures of the season will spare shady, middle and upper elevation terrain to some extent, but melt water will cause problems on the "already primed" slopes facing the southern half of the compass. The surficial wet loose avalanche problem should behave predictably today. However, all bets are off as the slabs and weak layers beneath them get wet for the first time. 

Today, we don't expect melt water to percolate all the way through 2-4 foot thick cohesive slabs; that story will play out in the coming days. However, we could see large, natural slab avalanches today in very specific locations: alpine cirques with lots of exposed rocks and variable snowpack depths. Here, melt water can gain easy access to buried weak layers as it enters the snowpack in thin areas and / or directly from the exposed rocks instead of from the snow surface. We've seen these "rapid onset" wet slab avalanche cycles in the Boulder and Pioneer Mtns in the past; large, 3-6 foot thick slab avalanches release in alpine terrain days or weeks before water has time to move from the snow surface, through the snowpack, to the weak layers. 

While this specific scenario is not likely to produce extensive wet slab avalanching today, it would not surprise us to see isolated large, wide, destructive natural avalanches. If you're playing in sunny, rocky alpine terrain, recognize there's an outside chance of this scenario occurring.  

  

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