Bollettino valanghe

Olympics

Northwest Avalanche Center
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Pericolo valanghe

Mon
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
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

More snow and strong winds will only make firm slabs more common and bigger. Blowing snow should help you decipher local winds and which steep slopes to avoid. In the western portion of the range, greater snow totals could result in more dangerous conditions than near Hurricane Ridge and the eastern half of the zone. 

Problemi valanghivi

  • Wind Slabs

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

    With more snow and strong winds in the forecast, it won’t take much searching to see what the problem is. Blowing snow will likely hit you right in the face. Strong and gusty winds might build slabs in some strange places like well below ridgelines. Loading patterns may be more erratic and variable than normal. 

    Take note of where the snow is depositing, and avoid steep slopes in these areas. New wind slabs might form over firm crusts or soft weak snow. In both cases, this could allow them to trigger easily. Expect bigger wind slabs at higher elevations and later in the day as more snow piles up.

    (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

There’s a pretty significant difference in how this storm is impacting the Olympic Mountains. Expect substantially more precipitation and higher avalanche danger in the western portion of the zone. This could include natural avalanches during and immediately following heavy precipitation and blowing snow. 

Conditions were pretty stormy in the Olympics on Saturday. NPS rangers reported gusty winds, blowing snow, and drifting at Hurricane Ridge. As temperatures rose, conditions became wet with a mixture of rain and snow. While there should be a brief reprieve in the storm Saturday night, continued strong winds and more precipitation are expected on Sunday. 

Prior to this storm, the snow surface was very aspect dependent. Southerly slopes formed a stout melt-freeze crust last week. This surface may be very firm and smooth in some places. On more northerly aspects, several inches of dry snow capped the 3/4 crust. Surface hoar was observed before snow started to fall. It’s a bit uncertain if these weak grains survived the warm temps and wind before getting buried. This weak layer would be most common in middle and upper elevation, shaded, sheltered slopes. If you see the new snow cracking, or feel it collapse, this could be the culprit. Quick hand pits can help you look at the bond between the old surface and new snow. 

Near and below the rain-snow line, wet heavy snow may slide easily over these old snow surfaces. These wet loose-ish avalanches should be fairly small and not pose too much of a hazard. Don't let one push you into an open creek or carry you over rocks. 

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