Bollettino valanghe

Stevens Pass

Northwest Avalanche Center
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Pericolo valanghe

Wed
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato
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Non aggiornato — questo bollettino è scaduto 2 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Stormy weather will increase the avalanche danger Monday night into Tuesday morning. You may trigger avalanches on steep slopes near and above the rain-snow line. If the sun comes out in the afternoon, things could change quickly, including seeing natural wet avalanches.

Problemi valanghivi

  • Loose Wet

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

    You could encounter a wide variety of wet avalanche issues on Tuesday. In simplest terms, be leery of any slope where you encounter wet, sticky snow regardless of aspect, elevation, time of day, or weather. 

    We’re most concerned with areas near and just above the rain-snow line. Here, you’ll find heavy and thick new snow. It often teeters on the edge and is ready to slide. A bit of rain, a moment of sunshine, or a period of warming temperatures… avalanche. These wet slides may blur the lines between loose and slab, wet and dry. While they can be easy to predict and manage, they often run the length of the slope and entrain additional recent snow. Don’t let one take over a cliff or into a creek. 

    Natural avalanches could occur during this cycle. They are most common near and below rocky slopes as blobs of snow shed from cliffs and trees. If the sun comes out and temperatures rise, you may see a barrage of rollerballs and wet slides. Pay attention to what’s above you, and don’t linger in this terrain. With all the recent and new snow, some of these slides could grow big enough to bury you.

    (3/24/2024)

    Example: A natural wet avalanche from recent snow. You often see these near and below rocky slopes. 

    Photo: Willie Webster

  • Storm Slabs

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

    As you ascend, you should eventually transition into drier snow. At these higher elevations, fluctuating temperatures, heavy precipitation rates, and strong winds likely created an upside-down snowpack. Unless the wind stripped it down to the crust, any steep open slopes should be suspect. You’re most likely to trigger a slab avalanche on convex rollovers, very steep slopes, and in wind-loaded terrain. Hand pits, uptrack tests, and small slopes can all help you observe the new snow and see how it might fail. Expect the biggest and most dangerous slabs on features where the wind drifted the snow into firmer and deeper slabs.

    (1/11/2024)

    Example: Small test slopes like this can highlight unable storm snow. 

    Photo: Matt Primomo

Avalanche Discussion

This may not be a particularly big storm, but it’s a significant divergence from our recent weather. Add to that dynamic springtime weather and the challenges of wet snow avalanche forecasting, and you have the makings for potentially dangerous conditions. 

We’re mainly worried about the snow above the Early April Crust (4/2). Prior to this storm about 4-8 inches of recent snow was found above this layer in the Stevens zone. It produced numerous wet loose and “slab-ish” avalanches over the weekend. On Monday. Stevens Pass Ski Patrol reported this recent snow failing in snowpack tests just above the crust. Any avalanche could entrain snow down to this layer allowing it to grow larger than the storm totals might suggest. 

The mountains are still in their transition to spring. Plenty of snow is left to shed. Keep you’re eye out for overhead hazards and limit any time you spend underneath them.

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