Bollettino valanghe

Olympics

Northwest Avalanche Center
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Pericolo valanghe

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

In sintesi

Low-density snow will form slabs that you can easily trigger in steep wind-loaded terrain. Avoid large avalanche start zones with signs of active or recent wind loading. In steep, sheltered terrain, expect dry snow to run far and fast and could push you into unintended terrain such as over a cliff.

Problemi valanghivi

  • Wind Slabs

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

    Thursday's naturally triggered wind slab (pictured) serves as a strong reminder that winds have been destabilizing otherwise deep and right-side-up snow. W and SW winds will rely on 4-6" of expected fresh snow falling from the skied as new ammunition for slab development. Some slabs may be large and up to 2 ft deep by Wednesday. On N and E aspects, avalanches have more dry snow to entrain and these will also be the most wind loaded. Identify and avoid wind-loaded start zones. Cornices have formed in both directions, so this may not be the easiest clue. You should be able to identify which side of ridge winds have stripped down to firmer layers or crusts and steer around steep slopes on the other side which may have pillow-like drifts. If you spend time on lee slopes, give start zones a wider birth and seek wind-protected slopes less than 35 degrees. 

     

    (3/2/2023)

    Small natural wind slab with an estimated 12" crown, D1.5. NW, 5300 ft. Backside of Maggie’s.

    Photo: Sam Siemens-Luthy

  • Loose Dry

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

    Small dry loose avalanches were moving quickly in steep, wind-protected terrain on Wednesday. Expect surface snow to destabilize in terrain approaching 40 degrees or steeper. These avalanches warrant greater caution above cliffs, depressions in the terrain, or rocks.

     

    Example: A small dry loose avalanche, or sluff,

    Photo: Irene Henninger

Avalanche Discussion

Around 6" of snow fell on Thursday, bringing average snow depths to around 20" of right-side-up snow above the 1 cm 2/20 crust. We're monitoring a layer of slightly faceted snow just beneath the 2/20 crust. Although we don't believe this is a current cause for concern, it's always worth keeping an eye out for evidence to the contrary. If you hear whumphs or settlement, this layer may be problematic in your area. Likewise, if you experience more widespread slab formation due to higher-than-expected snowfall rates or graupel, dial back your terrain selection to exclude all slopes steeper than 35 degrees.

The photo gallery shows high rates of snowfall late in the day on Thursday, shooting cracks in wind-loaded terrain, and the best snow coverage of the season with forests now filled in above 4500 ft.

Regioni coperte