Boletín de aludes

West Slopes Central

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

Lo esencial

A multi-day warming trend means we'll see another round of wet loose avalanches spanning further than they did the previous day.  When snow gets wet, surface crusts break down, or snow starts sliding downhill, avoid steep slopes and the terrain beneath the steep slopes. Slab avalanches can occur up to a few feet deep in dry snow, so consider avoiding very large steep slopes especially in areas with high-consequence terrain. 

Problemas de aludes

  • Loose Wet

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

    On Friday, the intense sun will have to cook its way through the previous day's crust, but temperatures are forecasted to be a little warmer and we suspect we'll have another round of wet loose avalanche activity to look forward to. Easterly slopes will warm up first, before transitioning to south and then westerly slopes in the afternoon. The span of wet loose avalanches may be a little larger than the previous day. 

    Pay attention to snow beneath your feet and on nearby steep slopes. When you notice it becoming moist and if snow begins rolling downhill on steep slopes, steer around those areas and the lower angle terrain beneath those steep slopes. We don't expect wet loose avalanches to get too deep at this point, probably less than a foot in depth, but depending on the amount of heat we get from the sun and how deeply you're sinking into wet snow, there's a chance avalanches could run deeper. There is a small chance that a wet loose avalanche could step down and trigger a larger slab avalanche. 

    (3/16/2023)

    Small rollerballs and wet loose avalanches began running late morning on Thursday. Expect this to be similar on Friday. 

    Photo: Keeley Rideout

  • Wind Slabs

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

    Both the West North zone on the Snoqualmie zone have had several large slab avalanches in the past couple days, and we suspect conditions are similar to these locations in the West Central zone. A few people in the West North zone triggered avalanches and were taken for rides, and injured. One person sustained serious injuries on Slate Mtn in the Baker backcountry, and you can read the preliminary avalanche report HERE. You can read about another involvement in the Baker backcountry HERE. 

    Most of the avalanches we've seen don't fit cleanly into the wind slab category. Recent 2-3ft deep avalanches have likely been failing on the new snow/old snow interface. Some slopes slid while similar neighboring ones do not. We believe these avalanches are occurring in areas where wind may have deposited slightly thicker layers, but differentiating between the slopes that may slide and the neighboring ones that may not is borderline impossible. Surfaces in most areas look similarly wind-affected so you can't identify them that way. 

    As each day passes we believe the layer is gaining strength, but we still suspect someone could find one of these sneaky slopes and trigger a large, possibly unsurvivable avalanche on it. Consider shifting your travels to simpler terrain. Avoid steep and very large slopes, or areas that contain terrain traps like very steep, cliffy, or sparsely tree-covered terrain for the time being.  If you see any obvious red flags such as long shooting cracks from your feet or sled, or recent nearby avalanches, avoid nearby steep slopes also. When in doubt, steer around slopes greater than 35°. 

    (3/14/2023) A D1.5 avalanche which occurred on the south side of Baker on Tuesday. It was very similar to heavily ridden nearby slopes. Suspected crown height of ~45cm. W, 5800' Photo: Irene Henninger

Avalanche Discussion

Variable surfaces now exist, where lower elevation terrain and the southerly half will now start the day with a crust. It's likely to break down during the day and get moist. Along the same lines, during this first period of springlike warming, pay attention to nearby cornices. They're very large and overhanging. Travel quickly or avoid areas beneath them, and stay several feet away from their edges. If there's anything that is going to trigger a large avalanche, they're going to be it. 

About 2-3 feet of snow fell Sunday into Monday through much of the zone, and a few additional inches fell Tuesday night. The majority of the snow was relatively heavy. North-facing terrain will continue to hold onto dry snow while the skies remain clear, although temperatures will spike much higher on Saturday. 

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