Bollettino valanghe

Snoqualmie Pass

Northwest 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 last year. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

It’s been several days since temperatures dipped below freezing at the Pass. While there may be a weak crust in the morning, sunshine and warm weather will quickly cause the surface to become wet and unstable. Don’t linger under large rocky alpine faces where large slides could occur with no warning.

Problemi valanghivi

  • Loose Wet

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

    It’s hard to say if you’ll see lots of wet loose avalanches on Saturday, but conditions are lining up to make it potentially the most dangerous day of this warm spell. There are two versions of the same problem to manage. 

    The hardest to predict will be the chance for natural wet avalanches. Rocky slopes above your head could warm faster than where you’re standing. Pay attention to what’s above you and look for routes that limit your time under these overhead hazards. Snow shedding of rocks or cornices falling could trigger these slides. Some avalanches could grow large and dangerous. 

    The other is the possibility to trigger wet loose slides on steep open slopes. This is much easier to anticipate. A surface crust in open areas should limit the chance for these slides to start the day, but it won’t last long. Once you find wet sticky snow on the surface, you might trigger an avalanche in nearby steep terrain.

    Overall, this might be a good day to head home early, especially if you start to see signs of even small wet loose avalanches. Don't forget about the terrain you'll need to cross on the way back to the car. 

    Several days of rollerballs and wet avalanche on Alta Mt. Look how many start on rocks. (2/28/2025) Alta Image CC-BY-NC-SA 4.0 Photo: Charlie Hagedorn

Avalanche Discussion

Preliminary Report: On Friday, February 28, three snowmobilers were riding near Harts Pass in the East North zone when they triggered a large slab avalanche. Two riders were caught and carried. One rider was fully buried and killed. The other was partially buried and injured. NWAC is working with local avalanche professionals to conduct an investigation. Our deepest condolences to the family, friends, and community. (NE, 6,800ft HS-AM-D2.5-R4-O

We’re deep into a prolonged warm period. Temperatures have generally been above freezing since Wednesday morning. While clear skies should allow for some cooling at the surface Friday night, any freeze will likely be weak and shallow. With another warm sunny day on tap, what makes this one different? This time winds should be relatively calm and unable to keep the surface drier. That might be all that’s needed to see the scales tip and natural avalanches become more common. That said, these natural wet loose cycles are very challenging to predict and can occur in different parts of the zone at different times, or even, not at all. 

Isolated natural wet loose avalanches were noted Thursday and Friday at the Pass. While a few could be getting close to D2 (large enough to bury you), most were small and relatively harmless (D1-1.5). If natural avalanches become more common, they could also grow larger. If you start to see this type of activity, it’s time to get well away from large rocky faces. 

Any avalanche that occurs should be limited to the 12-18 inches of recent snow over the atmospheric river (AR) crust. This snow is well settled, generally strong, and well bonded to the underlying crusts. All these things could help limit avalanche activity. 

The only dry snow remaining seems confined to higher, shaded terrain. These areas are also generally wind affected, but any lingering slabs should be unlikely.

Regioni coperte