Bollettino valanghe

West Slopes Central

Northwest Avalanche Center
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Pericolo valanghe

Fri
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 4 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Wet avalanches are still possible and will remain a problem until the snowpack begins to consolidate.  Be aware of triggering avalanches in wet snow on steep slopes and also for natural avalanches initiating in overhead terrain. Avalanches in drier new snow layers are still a concern in the alpine.

Problemi valanghivi

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1.5–2.5

    Continued rainfall produced another round of natural and human triggered wet avalanches in West North. Less avalanche activity was reported from Stevens and Snoqualmie Passes in the last 24 hours. The upper snowpack over the Valentine’s Day Crust is wet, unconsolidated, and weak. Ski cuts on steep slopes could trigger loose wet avalanches that get larger and larger until they stop in flat terrain. Natural wet slabs, glide avalanches, and falling cornices remain a concern and could entrain large amounts of snow despite starting off small. 

    With slightly cooler temperatures the likelihood of encountering one of these avalanches should decrease. On the other hand, they will still be dangerous if they get moving. Avoiding these is not a timing issue - simply being in or directly under steep terrain puts you at greater risk. Periods of sun Thursday afternoon could trigger a round of rollerballs, large pinwheels, and small loose wet avalanches on sun exposed aspects. Many below treeline areas now lack sufficient snow cover to create avalanches as rain events and warm temperatures have melted away the snowpack.

    (3/1/2022)

    A very large (D2.5) natural avalanche occurred at Stevens Pass Resort while the mountain was closed on the 28th or that night. This ran from Cowboy Ridge onto a groomed run below.  SPMR patrol reported similar natural avalanches widespread throughout much of their terrain.

    Photo: John Meriwether

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    2–3

    In the last 4 days, alpine areas picked up 6-12” of precipitation that fell mostly as snow, especially above 6000’. This created deep slabs that formed over old, weak snow surfaces. It’s likely many of these paths avalanched naturally and the rest are adjusting to the load of new snow but unstable slabs could still be found. Anticipate higher danger on wind loaded slopes. If you make it to the alpine on Thursday give large unsupported terrain features a wide berth.

Avalanche Discussion

The widespread, natural avalanche cycle peaked a few days ago but avalanche activity continued through Wednesday in neighboring zones. Dozens of avalanches of all types and sizes to D3 were reported from the Baker Backcountry and Stevens Pass.  No observations have been submitted from West Central, likely due to poor weather and terrible snow conditions. The common theme amongst avalanche workers across the Cascades has been to minimize downhill travel through knee-wrenching deep, wet snow.

Farther north in the zone, the upper snowpack near treeline consists of 100cm of new snow with up to 130cm over the prominent crust layer buried on February 14th. Wet snow layers can be found throughout the new snow layering the snowpack drains. Cooler temperatures should bring about a rapid increase in strength but it will take more than one or two cold, clear nights for the snowpack to fully freeze and consolidate.

Regioni coperte