Boletín de aludes

East Slopes Central

Northwest Avalanche Center
Ver en el mapa

Peligro de aludes

Tue
Alta montaña
3 · Notable
Límite del bosque
3 · Notable
Bajo el límite
2 · Moderado
Open full map
Desactualizado: este boletín caducó 6 months ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Don't get lulled into a false sense of security by the beautiful, spring-like weather. Weak layers, capable of producing dangerous avalanches, are lurking in the upper snowpack. Choose terrain carefully and remember that all steep slopes are currently suspect, especially if they are wind-loaded.

Problemas de aludes

  • Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Likely
    Tamaño
    1–2

    This is the avalanche problem that should be shaping your travel plans on Monday. While the likelihood of triggering these layers is a point of discussion, there is no disagreement among anyone who has taken the time to look - they are there, and they are weak. This could result in dangerously large avalanches that break widely or even trigger remotely (from a distance).

    Due to last week's wind event, slabs could be thicker and potentially more sensitive in wind-loaded areas. As we add warmth to the snowpack, we introduce more uncertainty to an already unsettling problem. 

    This problem is difficult to diagnose in the field, so you likely won't receive much feedback before an avalanche occurs. Maybe you'll get a whumpfing collapse or a shooting crack, but that's not a guarantee. The best mitigation tool you have is terrain avoidance. 

    (3/1/2026)

    Snow machine triggered persistent slab avalanche in the neighboring East South zone on 2/28. [HS- AMu-R2-D2-O @ NE, 6700']

    Photo: Joe Dellaporta

  • Loose Wet

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1–1.5

    Apparently, turning the calendar to March means that spring has arrived, and with it, the threat of wet avalanches.

    There will likely be a surface crust first thing in the morning. But once it breaks down and the surface gets warm and sticky or you see snow shedding on steep slopes, you'll know that wet avalanche activity could soon follow. That will be your cue to head for shaded, low-angle terrain, staying aware of slopes above you.

    This avalanche problem is typically easy to manage, but with persistent weak layers lurking below the surface, it becomes more complex. In addition to fanning out and growing in size as they descend, the threat now exists that they will trigger larger and more dangerous persistent slab avalanches. 

    The same logic applies to cornice failures. A danger in their own right, they could be the trigger that collapses our weak layers during this heat wave.

    (3/1/2026)

    Wet avalanche activity in the neighboring Snoqualmie Pass zone on Sunday. Look for similar activity on sun-exposed slopes on Monday.

    Photo: Charlie Hagedorn [Image CC-BY-NC-SA 4.0 ]

Avalanche Discussion

On Thursday, February 26th, a skier was fully buried in an avalanche at Stevens Pass Resort. Despite a long burial time, the skier was successfully rescued by Stevens Pass Patrol and treated for non-life-threatening injuries. The avalanche occurred on a wind-loaded northwest aspect near 5,3000ft and likely ran on a persistent weak layer over a crust, 15-20" deep.

You can generally find 8-12 inches of snow over our persistent weak layers - the 2/13 buried surface hoar and facets around the 2/7 crust. This depth and the prominence of these layers may vary throughout our large zone, especially on sun-exposed slopes or at lower elevations. However, we have decent confidence that this poor snowpack setup exists throughout the zone, despite only a handful of data points. 

On Saturday, backcountry travelers observed numerous whumpfing collapses on Big Jim Mountain outside of Leavenworth. Over in the Wenatchees, the Mission Ridge Pro Patrol reported a fairly quiet day on Sunday, but noted that the weak layers are alive and well in their study plots. On Friday, NWAC forecasters were in the Teanaway and found that the buried surface hoar was starting to heal, but the 2/7 facets were not. They also observed long shooting cracks in wind-drifted snow.

We don't have many direct avalanche observations from our zone, apart from some slides near Mission Ridge roughly a week ago. However, in neighboring zones, we have gotten plenty of feedback. East North continues to have very large avalanches fail. Stevens Pass had a very active start to the weekend. And a snowmobiler in the East South triggered a persistent slab on Saturday that broke 2 feet deep. Given the known weak snowpack structure in our zone, these observations underscore the concerns you should consider when making your travel plans. Take the time to discuss your acceptable level of risk with your partners.

Regiones cubiertas