Bollettino valanghe

Olympics

Northwest Avalanche Center
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Pericolo valanghe

Sun
Alta quota
2 · Moderato
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto last year. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Stormy weather will create fresh slabs of snow along the sheltered sides of ridges and other features exposed to the wind. These potential avalanches should be more common at higher elevations and in the northern and western portions of the zone. Be leery of steep slopes when you see blowing snow.

Problemi valanghivi

  • Wind Slabs

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

    It will take a few hours for enough snow to fall to create any real hazard. In places that don’t receive much new snow, it might not happen at all. However, strong and gusty winds will have no problem drifting any dry snow into shallow slabs. 

    It should be pretty obvious if this issue is forming. You’ll see blowing snow on the ridges above you, or the airborne snow grains will be stinging as they hit you in the face. Watch which way the snow is blowing and where it’s landing. 

    These slabs should be fairly small, but they might trigger easily on underlying crusts or older weak snow. Don’t underestimate wind loaded slopes, especially in rocky terrain or above cliffs.

    (12/13/2024)

    Example: Is it windy? Don't overlook the obvious. Blowing snow should mean wind slabs until proven otherwise. 

    Photo: ONP Rangers

Avalanche Discussion

A narrow but potent atmospheric river will clip the northwestern corner of the Olympics on Saturday. This could result in significant precipitation in one part of the zone, while other areas remain dry. Expect avalanche danger to develop in places that receive more than 3-4 inches of snow by the end of the day. Elsewhere cloudy skies and strong winds should result in generally safe avalanche conditions. 

One big question for Saturday’s forecast is, “What’s the snow surface like, even if it’s buried by new snow?” Warm and sunny weather on Friday likely softened many slopes. With cloudy skies Friday evening it may be hard for this soft wet snow to refreeze. New snow might stick to any warm surface well. Or, if the wet snow freezes up, it could form a new crust for the new snow to slide easily over. In these locations, you could encounter very firm and slick conditions.

On shaded aspects Thursday, surface hoar and a few inches of soft snow were found over the 3/4 crust. The surface hoar may not have survived Friday’s warm temperatures or the overnight winds, but it’s worth checking. If you start to see the shallow new snow crack easily, that could be buried surface hoar. Below these crusts, the snowpack is generally stable.

Your observations help us build the next forecast.  Share what you see with us and your local backcountry community.

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