Boletín de aludes

Snoqualmie Pass

Northwest Avalanche Center
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Peligro de aludes

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

Lo esencial

This isn’t a very big storm, but you may trigger avalanches near and above the rain-snow line. Be leery of convex rollovers, very steep slopes, and wind-loaded areas where slides will be more likely. If the underlying snow isn’t frozen, avalanches could gouge deeper and grow larger.

Problemas de aludes

  • Loose Wet

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

    Wet heavy snow will accumulate near and just above the rain-snow line. This is the elevation band where you should be most worried about triggering a wet loose slide. It may not seem like much snow, but it could move easily downhill. Wet sticky snow, fresh rollerballs, and small slopes that sluff below you all highlight the elevation band and the problem. 

    In general, these avalanches will be small and only involve the surface snow. In these cases, don’t let them push you over a cliff or into a creek. However, if the snow underneath is also wet and weak, these avalanches could entrain deeper layers and grow much larger. Give these bigger, deeper wet loose slides a wide berth. 

    If the sun comes out, rain reaches higher in the terrain, or temperatures spike, you may see a barrage of rollerballs and even several natural wet loose slides.

    (3/24/2024) This natural wet loose avalanche occured on Sunday and covered a common travel route from the morning. 

  • Wind Slabs

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

    Somewhere as you ascend the snow will transition from wet, to moist, to dry. At these higher elevations, moderate winds may drift the new snow into slightly firmer and deeper slabs. Look for blowing snow and drifts to point toward the wind-loaded pockets you want to avoid. You’re most likely to see pillow-like slabs along exposed ridges, near the base of cliffs, and in the tops of chutes. Even though they should be small, don’t let them surprise you in high-consequence terrain.

    (2/18/2023)

    Example: Signs of wind loading to look for Saturday.

    Photo: Dallas Glass

Avalanche Discussion

A weak storm system will impact the Pass Sunday night and Monday. Even though it’s not very big, it’s enough to present new hazards. It’s also springtime and conditions this time of year are more dynamic than mid-winter. Daytime heating, a few breaks in the clouds, or even rain to higher elevations than anticipated can all cause conditions to change rapidly. Don’t base your decisions on a few observations from the morning. 

This storm will bring slightly cooler temperatures to the zone. This will help reduce the danger of glide and other “shed” style avalanches. However, they won’t stop on a dime. Pay attention to the terrain above you and limit any time you spend below rocky faces that still hold patches of snow. One such avalanche occurred on Sunday when a block of snow fell off a cliff in the Alpental valley. 

Many travelers around the zone reported natural and easily triggered wet loose slides. Most of the natural avalanches released in steep rocky terrain receiving direct sunshine, but human caused slides occurred on most aspects. One traveler was caught and carried by an avalanche near Source Lake. Fortunately, the person was not injured by the shallow but wide slide. Some of this wet snow may freeze overnight, but given the increasing clouds and mild weather, that’s not certain. 

At lower elevations, the recent warm weather took a toll on the snowpack. Tree debris, holes, and open creeks are common, especially below 4000ft.

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