Boletín de aludes

Snoqualmie Pass

Northwest Avalanche Center
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Peligro de aludes

Wed
Alta montaña
3 · Notable
Límite del bosque
2 · Moderado
Bajo el límite
2 · Moderado
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Desactualizado: este boletín caducó 2 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

A messy storm will bring dynamic conditions to the Pass on Tuesday. The danger will increase in the afternoon and likely peak overnight. Make flexible plans that let you quickly retreat to the trailhead if conditions get spicy sooner than expected.

Problemas de aludes

  • Storm Slabs

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

    Snow totals from this storm, continue to grow. At this point, several inter-storm layers could produce avalanches in the right terrain. With temperatures expected to warm Monday night and throughout Tuesday, this could turn the snowpack “upside-down” and make it easier to trigger avalanches. 

    While the most touchy slabs should be thin and small, in a few isolated areas they could entrain soft snow, or possibly step down causing slightly older layers to fail. Both could result in avalanches big enough to bury you. 

    Hand pits, up-track tests, and small slopes will help you assess the newest snow, but you’ll need to look all the way down to the start of the storm (12/13) and maybe a little deeper (12/7), to get the full picture. While shallow slabs might occur on any steep open slope, large avalanches will be most likely near large convexities, on unsupported slopes, and in wind-loaded terrain.

    Most of the recent avalanche activity has been in complex and rocky terrain. In these areas, even small slides could have very high consequences. 

    (12/15/2024)

    A skier triggered avalanche in the Snoqualmie Pass Zone on Sunday.

    Photo: Tom C

Avalanche Discussion

Tuesday’s weather is nasty, complex, and full of uncertainty. This results in the potential for rapidly changing conditions. Temperatures are expected to warm, but the bulk of the rising temperatures should hold off until overnight. We expect rain to reach well above the peaks in the area, producing very dangerous conditions, and large natural avalanches. Tuesday night won’t be a night for winter camping. Simultaneously, freezing rain will likely coat lower elevations near and east of the Pass in ice, limiting the avalanche hazard. 

All this to say, if the warm-up, rain, and freezing rain are early, conditions could get quite dangerous. Don’t get over-committed by being too far from the trailhead. Choose routes that let you quickly head home if things look like they are turning warm and wet. 

Since Friday (12/13) the pass has picked up 18-24 inches (45-60cm) of snow and counting. This resulted in a few human triggered wind and storm slabs. Avalanche professionals near Snow Lake Divide also reported rolling collapses and sudden test results. The culprit? Likely a thin crust (12/13) at the base of the recent storm snow. These observations only increase the uncertainty about how all this snow will respond on Tuesday and into the rain event 

These storms significantly improved travel conditions at lower elevations, but it’s still thin. Give yourself time to manage all the creeks, logs, bushes, and trees.

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