Bollettino valanghe

West Slopes South

Northwest Avalanche Center
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Pericolo valanghe

Fri
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
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In sintesi

With no overnight refreeze and rising temperatures on Thursday, both natural and human-triggered wet loose avalanches are possible. Avoid steep slopes nearby if you see rollerballs, recent wet slides, or are sinking into mushy snow. High-elevation slopes that were unaffected by Wednesday’s warmth may prove especially reactive to Thursday’s heat.

Problemi valanghivi

  • Loose Wet

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

    After a day of sun and warmth on Wednesday, we suspect the snow surface on all but some high-elevation shaded slopes to be wet or at least moist. Anticipate widespread wet and mushy surface conditions and for wet loose avalanche danger to be present from the start of the day.

    While we don’t expect conditions to be quite as reactive as they were when the fresh snow first baked on Wednesday, wet loose avalanches will remain possible, and some could grow large enough to bury or injure a human. These slides may climb to higher elevations and wrap onto steeper, shadier slopes than you might expect. If you find dry snow at the surface, be especially cautious—once it starts to wet, it can become reactive quickly. With tons of wet snow below the surface, even small slides could gouge deeper and run larger. While we're not expecting big slides to start at lower elevations, slides that start higher could descend down low. 

    Unfortunately, we also need to consider some lower-likelihood but higher-consequence wet avalanche problems. Wet or glide slab avalanches, cornice failures, and large chunks of snow peeling off rock faces (“blob-a-lanches”) remain plausible. You’re unlikely to trigger these yourself—but if one goes, it could be large and destructive. Managing this kind of uncertainty is personal, but acknowledging it and planning accordingly is key. If you're traveling on or below avalanche paths, minimize your exposure and keep moving to reduce the chances of being in the wrong place at the wrong time.

    (4/9/2025)

    A large natural wet loose avalanche observed Wednesday in the Crystal Backcountry. This slide entrained significant amounts of snow as it descended, as can be seen in the sizeable debris pile.

    Photo: Andy Harrington

Avalanche Discussion

Between 6–16" of snow fell from Monday through Wednesday morning at middle and upper elevations, varying by location and altitude within the zone. On Wednesday, NWAC forecasters and Crystal Pro Patrol observed numerous wet loose avalanches in the nearby backcountry, some of which were large. Patrol also triggered a few reactive, thin dry slabs during control work. They noted the 4/7 crust beneath the recent snow to be supportable on skis, but not to poles or boots. 

While we suspect most lingering dry slab instabilities have settled out, if you find cold, dry snow on Thursday, there remains a slight chance of triggering a pocket of wind-drifted snow—especially in complex, confined terrain near ridgelines or the tops of gullies.

The snowpack is currently stuck in a slow and uneven transition toward spring. There’s free water moving within, some wet layers and interfaces, and significant portions that remain dry and wintry. In other words, it’s neither fully frozen nor fully transformed into a stable, well-drained spring snowpack. Big wet slides are unlikely—but not entirely off the table. Build a wide margin of safety into your day, and approach each slope with an open mind.

Finally, while we don't expect a little spritz of rain will be enough to tip the avalanche scales on Thursday afternoon, it's always a reasonable idea to call it a day when rain is falling on snow, especially if it is coming down heavier than expected.

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