Bulletin d’avalanche

Banner Summit

Sawtooth Avalanche Center
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Danger d’avalanche

Fri
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré
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Périmé — ce bulletin a expiré last year. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

You could trigger a large wet snow avalanche, and some may occur naturally. You can reduce your risk by travelling on colder, supportable snow and avoiding areas where you sink into a mushy, wet snowpack. Cornices are large and may be unstable—give them a wide berth. 

Problèmes avalancheux

  • Wet Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    2–2.5

    Large wet slab avalanches are most likely at middle and upper elevations where meltwater reaches buried weak layers. Weak layers of facets and crust + facet combinations are most prominent above 8000' on slopes facing E-NE-N-NW. Very warm temperatures and warm sunshine pushed meltwater deep into the snowpack. Last night's temperatures remained above freezing, allowing meltwater production to continue. The potential for large wet slab avalanches will remain until the snowpack fully drains or refreezes.

    This problem is hard to predict and not easily managed. Your best bet is to avoid travelling through and under avalanche paths with cliffs or rock outcroppings near the start zones.  

    (3/26/2025) Wet Slab on McGowan Pk in the Sawtooths. Photo: Sawtooth Avalanche Center

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2

    Wet loose avalanches are possible on steep slopes. Rollerballs and a slushy snow surface are clues that the snow is heating up, and wet avalanches may soon follow. Although beginning small, they can grow large enough to knock you off your feet or bury you in channeled terrain. Even small slides are consequential above terrain traps such as gullies, creeks, and thick timber. Avoid lingering under big avalanche paths and steep, rocky slopes during the heat of the day.

    Additional Discussion: Cornices are large and may be unstable. Some may release naturally. They can break further back than expected—give them a wide berth when traveling along ridgelines.

    (3/26/2025) Wet loose activity in Meadow Basin, Sawtooths. Photo: Sawtooth Avalanche Center

Avalanche Discussion

Tuesday in the Boulders, we made this short video explaining a typical progression of wet snow avalanche problems. Sun on dry snow can create meltwater at the surface, causing rollerballs or pinwheels. Extended sun will wet a thicker layer of snow at the surface, and before long, these rollerballs are joined by small wet loose avalanches. Continued melting at the surface can push water deeper into the snowpack, allowing for larger, gouging wet loose avalanches or destructive wet slab avalanches. So where do we sit today?

Today's cooler temperatures and cloud cover will slow meltwater production, which is a good thing, but wet avalanche concerns remain. The snow surface will not be as wet today as yesterday, and loose snow avalanches are less likely. More concerning, however, is the meltwater we've already pumped into the snowpack, especially on slopes facing away from the sun. Upper elevations have been above freezing for two full days, allowing meltwater to make its way deeper, increasing the chance for a surprisingly large, wet slab avalanche.

The slope-to-slope variability is high. Subtle differences in terrain orientation, wind, and cloud cover can make a huge difference. Rather than trying to predict which slope is on the brink of failure, I'm more comfortable knowing that I simply don't know. This uncertainty leads me to safer, lower-angled, simple terrain that minimizes overhead exposure. I'd recommend a similar approach. Give yourself wide safety margins and limit time spent under large avalanche paths. 

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