Bollettino valanghe

West Slopes South

Northwest Avalanche Center
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Pericolo valanghe

Wed
Alta quota
3 · Marcato
Limite del bosco
2 · Moderato
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

A break between storms should help the snowpack start to heal. However, in certain parts of the zone, several feet of snow fell. This might not be the time to step out into bigger terrain. You can still trigger avalanches on very steep, convex, or unsupported slopes.

Problemi valanghivi

  • Storm Slabs

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

    For most of the zone, recent storms left 1.5-3+ feet of new snow, with the highest totals on the volcanoes. It will take more than a quick moment for all this new snow to heal. Warming temperatures, periods of wind, and changes in precipitation rate created several possible inter-storm layers that could still fail. Look at all the new snow down to the 2/13 interface. This could be a crust on S aspects or old settled powder or facets on shaded terrain. 

    Uptrack tests, hand pits, and small slopes can all give you an idea of how the new snow may behave. Just make sure you’re looking at all the recent snow. In deeper areas, this could be tough for these quick-moving observations. 

    Give complex, consequential, and wind loaded slopes a wide berth. Fortunately, there’s still fun soft snow on most slopes in the middle and upper elevations.

    (2/15/2025)

    A handful of natural slab avalanches were reported on Mount Adams on Sunday. Many of them occurred near rocky features or on convex slopes.

    Photo: JB

  • Persistent Slabs

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

    After nearly a week of being quiet, the persistent weak layers decided to speak on Monday (2/17). They let out a large rumbling whumpf on a W aspect at 5800ft near Mt Rainier as if to say, “don’t forget about me.” It’s easy to wish this layer away, but this type of data is exactly why we shouldn’t. Weeks worth of snowpack data continues to show if you found the “sweet spot” it could produce a large nasty avalanche. 

    While this layer “spoke” today, don’t expect such a clear sign. It’s already given us plenty. The only way to manage this problem with any certainty is avoidance. Steering away for large steep open shaded slopes helps you avoid the problem.

Avalanche Discussion

Tuesday’s break in the storm should help the likelihood of avalanches to slowly drop, let the snowpack settle, and give us a moment to take stock of impacts from the recent storms. While we don’t expect much clearing, you could see some sunshine, particularly near the crest. If this lasts longer than expected, there may be a barrage of rollerballs and possibly some small natural wet loose avalanches. 

These storms have been very uneven across the zone. Places like Mt Rainier and Mt Saint Helens were left with 2-3 feet of snow, while Crystal received less than a foot. This combined with periods of strong winds from multiple directions has added to the small and large scale variability in the upper snowpack.

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