Bollettino valanghe

Stevens Pass

Northwest Avalanche Center
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Pericolo valanghe

Sat
Alta quota
2 · Moderato
Limite del bosco
1 · Debole
Sotto il limite
Senza grado
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Non aggiornato — questo bollettino è scaduto 8 months ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Most of the snow is gone at low and mid elevations after this week's deluge. Stay out from under rocky terrain features and corniced ridgelines that still have wet snow to shed. Access to mountain terrain is difficult due to numerous road closures, landslides, and flooding.

Problemi valanghivi

  • Loose Wet

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

    There is still a chance of seeing steep, rocky terrain shed wet snow, or cornices fall off ridgelines with meaningful snow cover. The main danger isn't so much triggering a wet avalanche on steep snow-covered slopes; it's that wet, saturated snowpacks tend to unload sporadically even after precipitation ends. Keep an eye on what is above you if you make it into the mountains, and don't linger under anything else that looks wet, sketchy, and poorly attached to the mountain.

    You might find new snow and fresh wet avalanches if you make it to upper elevations. Pay attention to new snow depths and rising snow levels as you gain elevation.

    (1/16/2021)

    Sparsely snow-covered cliffs like these can continue to shed snow until temperatures cool or it all melts away.

    Photo: Irene Henninger

Avalanche Discussion

Concern about avalanche danger seems a bit trivial compared to the damage to infrastructure and property on both sides of Stevens Pass. No direct observations of avalanche activity were reported. Difficult access and much bigger concerns kept nearly everyone out of the mountains on Thursday. It’s a safe bet that upper and some middle elevation areas experienced natural activity in the form of wet loose and other types of wet avalanches due to heavy rainfall. Much of the meager snowpack that had been holding on at mid-elevation got washed away and is heading down creeks and rivers on both sides of the pass. 

Despite overnight weather station outages, two stations that remained online indicate that some new snow fell at upper elevations as temperatures cooled. The Dirtyface temperature gauge showed readings near or below 32°F from 2:00 am into Thursday afternoon. In the same time block, the Berne gauge picked up about 1” of precipitation. While it’s impossible to turn vague data into actual snowfall amounts, it seems likely some new snow did accumulate up high. 

Unfortunately, any dry snow up there won't last long, with periods of light precipitation and rising snow levels heading into the weekend. While additional warming and a bit of rain shouldn't cause much additional damage at mid elevations, it could get a reaction from new snow up high.

With the warm start to the 25-26 winter season, we have less snowpack information than usual to start daily forecast operations. For zones and elevation bands with less snow than needed for avalanche hazard, we will issue a forecast with No Rating. Anticipated avalanche and weather conditions will still be updated daily. NWAC will issue an avalanche danger rating for a zone when enough snow to produce avalanches has accumulated at middle and upper elevations.

 

 

 

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