Bollettino valanghe

West Slopes South

Northwest Avalanche Center
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Pericolo valanghe

Mon
Alta quota
3 · Marcato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
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Non aggiornato — questo bollettino è scaduto 8 months ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Sunday should provide a relative break in the relentless stormy weather. However, with so much recent snow, approach any steep open slope with caution. Expect the most dangerous conditions higher in the terrain, in wind affected areas, and on more complex slopes.

Problemi valanghivi

  • Storm Slabs

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

    Observations from across the zone on Saturday reported primarily loose and unconsolidated snow over the most recent crust (Dec 18). It’s hard to say exactly how that will change Sunday as temperatures warm.

    Given this setup, be wary of steep open terrain. Small slopes, uptrack tests, and hand pits can help you see how the new snow reacts. If it fails in blocks or produces cracks, it's forming a slab. Steer away from nearby open slopes. If it sluffs, then you’re mainly dealing with loose dry avalanches. With 12-20 inches of new snow, make sure to check all the way down to the crust. If you aren’t reaching this layer, then you aren’t seeing the whole story. 

    With the dynamic weather, snow conditions could change from morning to afternoon. Sunshine is even possible in a few locations. If the sun comes out, expect natural loose avalanches on rocky slopes. 

    Things get even more complicated at higher elevations, where the wind likely drifted snow into slightly firmer slabs. However, a few inches of powder may hide obvious clues. Watch for wind lips and subtle drifts to indicate possibly wind loaded slopes. 

    (12/20/2025) Uptrack tests like this one, can highlight slabs and weaklayers with the recent snow.

Avalanche Discussion

Happy Winter Solstice! The mountains finally look and feel like winter thanks to a colder, snowier pattern over the past several days. On Thursday, rain reached at least 6000ft and formed a new crust (Dec 18). We’re primarily worried about the snow over this prominent snowpack marker. On Saturday, observations reported 12inches near Crystal, 15inches near Paradise, and more than 18inches at White Pass over this crust, with a few more inches on the way.

While precipitation should taper on Sunday, that’s quite a bit of new snow. There’s even a chance for some sunshine, particularly in southern and eastern areas. Mt Rainier could become the anomaly, with showers and clouds persisting. This might result in slightly more dangerous conditions within the National Park. 

It’s still early, and our information is limited, but thanks to our professional partners, we’re piecing together what the snowpack story across the zone. Snowdepths generally increase substantially above 6000ft in the northern part of the zone and 6500ft further south. The snowpack has three main parts: the recent storm over the Dec 18 crust, a mid-pack of dry snow over the mid-December crusts, and the old atmospheric river ‘snow’ from earlier this month. 

Conditions remain very thin despite all the recent snow. Anticipate travel challenges, particularly in the forest. With so many things to hit, even a small slide could result in a very nasty ride. 

The weather over the past few weeks has been extraordinary, with torrential rains, extreme winds, flooding, and landslides. Many communities are dealing with damage to homes, infrastructure, and businesses, stretching resources thin. These events have limited access to the mountains for all of us. State and local resources are working diligently to reduce the worst of these impacts. We can help by being respectful of local communities, obeying road closures, and heeding ski area uphill travel policies.

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