Bollettino valanghe

Sawtooth & Western Smoky Mtns

Sawtooth Avalanche Center
Vedi sulla mappa

Pericolo valanghe

Sun
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato
Open full map
Non aggiornato — questo bollettino è scaduto 6 months ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Dangerous conditions exist. You can trigger a large avalanche on many slopes where the wind formed drifts or stiffened the snow surface. Triggering avalanches is also possible on steep slopes that are sheltered from the wind. You may be able to trigger slides remotely—from flat terrain below, above, and to the sides of steep slopes. Beware of small wet avalanches releasing on their own on very steep slopes once surfaces become moist or wet. 

Problemi valanghivi

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    2–3

    We are a few days out from the most recent storm. Days ago, snowmobilers remotely triggered a Persistent Slab avalanche north of this zone near Bull Trout Lake (photo), and riders remotely triggered cornices and slabs beneath them on Osberg Ridge (details). We've seen over 100 avalanches failing naturally on these same weak layers.

    You're most likely to trigger a wide, 1.5-4 foot thick slab avalanche on steep slopes that tilt away from the afternoon sun (NW-N-NE-E-SE) where you find wind drifts, slabs, or wind-stiffened snow at the surface. Avalanches could fail on multiple weak layers (facets, surface hoar, crusts + facets or surface hoar) buried by the series of February storms. While wind-loaded terrain is most widespread at upper elevations, Wednesday's strong W-NW winds formed slabs or stiff snow surfaces on more middle and lower elevation slopes than usual.

    Persistent Slab avalanches can release in surprising ways:

    • They can be much wider than expected (view many recent examples here).
    • They can break above you and pull into relatively gentle terrain.
    • You can trigger them remotely—from flat terrain below, above, and to the sides of steep slopes.  

    Unfortunately, the best way to avoid trouble is to give avalanche terrain a wide berth. This includes gentler terrain below and above steep slopes. 

    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) Large natural avalanche near the mouth of Smiley and Frenchman Cks. N aspect @ 8,600'.

    Photo: Sawtooth Avalanche Center

Avalanche Discussion

Earlier this week, new snow and strong winds overloaded buried weak layers, pushing them past their breaking point. Over the past several days, we’ve observed more than 100 natural avalanches and a handful of remote-triggered slides (view chart and Avalanche occurrences). With this much evidence, there is little uncertainty about the snowpack’s stability– conditions are sketchy. 

Three weak layers are buried within the upper 1-3 feet of the snowpack. We’ve seen avalanches fail on all three within the past week. The most likely terrain for similar slides is middle and upper elevation slopes facing NW–N–NE–E–SE, though sunny 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 slopes facing the sun (SE-SW–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 harbor the ingredients for slab avalanches, with 1-3 foot thick slabs resting on weak, faceted snow.

Additionally, warm temperatures today could cause wet-loose avalanches, especially if the cloud cover arrives later than expected. Very steep, wind-sheltered slopes where the snow surface is not wind-hammered or hardened are most likely to produce wet avalanches. Don't linger below large, sun-drenched avalanche paths. 

Regioni coperte