Bollettino valanghe

Galena Summit & Eastern Mtns

Sawtooth Avalanche Center
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Pericolo valanghe

Wed
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 4 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Triggering a 1-2 foot thick avalanche in wind-affected terrain remains possible. Last night, 2-4 inches of snow fell with moderate winds and created fresh wind drifts along ridgelines and exposed terrain. Avalanches failing on deeper weak layers are less likely but can't be ruled out in rocky, wind-affected terrain. 

Problemi valanghivi

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1.5–2.5

    What is it? Overnight a storm brought 1-3 inches of lightweight snow, accompanied by moderate winds from the NW. Several weak layers consisting of facets, crusts, and/or surface hoar exist in the upper snowpack. Triggering an avalanche on any of these layers is most likely in wind-affected terrain steeper than about 35 degrees.

    Where is it?  Expect to find at least one of these weak layers on most slopes in the mid and upper elevations. Most of them are more dangerous in areas with recent wind-affect. Older weak layers (crusts and/or facets) can be found in rocky, wind-affected, alpine terrain where the snowpack is less than 3 feet thick (see Ethan's video at right/above).

    How can you recognize it? Look for wind-affected snow near ridgelines, prominent features, and on the sides of gullies or chutes. Cracks shooting out from your machine or skis clearly indicate an unstable slab. Even small slabs that knock you off your feet and send you downslope can carry high consequences in the wrong terrain (photo here).

    How can you manage it? You can reduce your risk by avoiding very steep (greater than about 35 degrees), with hard or stiff wind-blown snow at the surface—especially those with ugly consequences if caught in an avalanche. Persistent slab avalanches may break wider than expected or higher on the slope above you. 

    ADDITIONAL DISCUSSION:  Fresh wind slabs likely formed in exposed middle and upper elevation terrain. These slabs will be on the smaller side but may overlay older generations of hard slabs. They can "step down" into the weaker layers mentioned above.  Staying off recently wind-loaded slopes steeper than about 35 degrees is an excellent way to not tangle with these small avalanches. 

Avalanche Discussion

A STORM BRINGS CHANGE

A small storm brought 2-4 inches of lightweight snow, accompanied by moderate NW winds. While it might not be a widespread dramatic change,  this nudge of snow mixed with moderate winds continues to build a slab over various weak layers.  The snowpack here hasn't received as much snow during January, and the weak layers we buried in November, December, and January are all still "in play." Slides on weak layers closer to the surface are more likely, but large avalanches failing on weak snow deeper in the snowpack can't be ruled out. You're most likely to get into trouble in places with stiff wind slabs and drifts resting on a weak, faceted snowpack in rocky, wind-affected, alpine terrain. Lots of terrain looks like this in the Pioneer, Boulder, and White Cloud Mountains, which make up most of this zone.

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