Bollettino valanghe

Galena Summit & Eastern Mtns

Sawtooth Avalanche Center
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Pericolo valanghe

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

In sintesi

Wet snow avalanches are possible in steep, rocky terrain receiving direct sun—be wary of traveling on or below these slopes, especially later in the day.  Cornices are large and may be unstable—give them a wide berth. Triggering a large slab avalanche is unlikely, but if you were to find trouble, it would be on steep slopes facing the northern two-thirds of the compass, especially in the southern part of this zone where the snowpack is thinner.

Problemi valanghivi

  • Loose Wet

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

    Loose snow avalanches are possible on very steep, rocky slopes receiving direct sun. Avalanche activity is most likely on S-facing slopes by midday and on W-facing terrain this afternoon. These slides often initiate near the base of trees and rocks, gathering snow and growing in size as they move downhill. Rollerballs, or pinwheels, signify that the snow is heating up, and wet avalanches may soon follow. A mushy, wet snow surface indicates that stability is deteriorating and the likelihood of triggering a slide is increasing. 

    While most will start small, they may will grow large and dangerous or push you into unwanted terrain. Some slides have the potential to flank out into wider wet slab avalanches. Even small slides are consequential above terrain traps such as gullies, creeks, and thick timber. Plan your day to avoid lingering under steep, sunny slopes when the sun is out.

    (2/27/2025)

    Small, natural wet loose slides in the N. Boulders.  These slides occured sometime last Thursday or Friday, near 10,000' on a SW aspect. 

    Photo: Sawtooth Avalanche Center

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely
    Dimensione
    2–2.5

    Slabs exist above widespread, weak layers (facets, surface hoar, crusts, and combinations). Persistent Slab avalanches are most likely in the thinner snowpacks of the Pioneer and Boulder Mtns in the southeastern part of this zone. Before triggering an avalanche, you're unlikely to experience obvious signs of instability like snowpack cracking and collapsing or whumpfing. Persistent Slabs can release in surprising ways and break much wider than expected. You are most likely to trigger a dense, 2-4 foot thick avalanche where:

    • The snowpack is less than 4 feet thick—relatively shallower spots may exist where the wind frequently blows, and the slab is not uniformly thick.
    • Any part of the slope you are on or connected to is steeper than about 35 degrees
    • The slope faces the northern 2/3 of the compass
    • A smaller wind slab or loose snow avalanche overloads the buried weak layers

     

    (2/26/2025) Large slab avalanche on Boulder Peak, Boulder Mountains. SE @ 10,000'. Photo: Sawtooth Avalanche Center

Avalanche Discussion

Without a solid freeze overnight, the upper snowpack has remained wet, and any thin surface crusts formed overnight will quickly break down on slopes basking in unobscured sunlight. Today's wet snow problems will follow the sun's path—E and SE in the morning and S, SW, and W in the afternoon. Many slopes have already shed and slid naturally over the past few days of strong sun and warm temperatures, so widespread naturals or signs of instability, like rollerballs or pinwheels, may not be obvious. If you encounter a wet, mushy snow surface, you could trigger a wet loose slide, particularly on very steep, sun-drenched slopes. To manage this, avoid lingering under or traveling on steep slopes during the heat of the day or where the upper 5–8 inches of the snowpack is wet and mushy.

Be wary of traveling near or under hanging cornices. Warm temperatures may cause these overhanging cornices to sag and fail. 

Triggering a large persistent slab avalanche is unlikely. If you were to find trouble, it would be in the shallower, wind-swept southern portion of this zone where the snowpack is thinner (less than about 4 feet). While this southern portion of the zone harbors the shallowest and likely highest chance of triggering a large slab avalanche, don't rule out the possibility of finding trouble elsewhere. We have observed a couple of very large slab avalanches in the Boulder Moutains that likely happened following a strong wind event on Monday night. 

Regioni coperte