Bollettino valanghe

Stevens Pass

Northwest Avalanche Center
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Pericolo valanghe

Fri
Alta quota
2 · Moderato
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 5 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Expect cold temperatures, sun, and relatively calm wind on Thursday.  You may be able to trigger slab avalanches on steep slopes in areas of recently wind-drifted snow. Steer around fresh wind drifts just below ridgetops at upper elevations

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–1.5

    Use caution on wind-exposed slopes 35 degrees and steeper and just below ridges. You can stay safe by steering around pillows of wind-drifted snow and by sticking to lower angled or wind-sheltered slopes. Wind slab avalanches are most likely at the highest elevations where drifts will be more consistent and could be deeper.  Pay attention as you move into wind-exposed terrain higher in the mountains. Anticipate that you may find wind-drifted slabs in unique locations. Watch for cracks in the snow and stiffer, sculpted surfaces as indicators of wind slab avalanches.

    Winds Monday night into Tuesday transported snow on a variety of slopes, especially on the highest ridges. While the dominant wind direction was easterly, localized terrain channeled the wind in a variety of directions. Across the zone, wind slab avalanches could be triggered in very specific locations. Locations like Tye Peak and the moonlight area saw wind loading. Even higher ridgelines that are sheltered from the major east-west running valleys (such as Josephine Peak or Arrowhead Mountain) may not have seen as much wind effect. Older slabs that formed from west winds on Saturday are now difficult to trigger. 

Avalanche Discussion

For Thursday, expect a dusting of snow overnight yielding to sunshine and relatively warmer temperatures, though still cold. Cold temperatures have been preserving and weakening light, dry snow on the surface of shaded northwest through east aspects.  You may be able to trigger small loose avalanches in the surface snow on very steep, wind-sheltered slopes. A storm brought about 2.5 feet of snow to the top of Stevens Pass Saturday through Sunday with some westerly winds. 

Observers reported wind transport and fresh slabs of wind-drifted snow near and above treeline on Tuesday. On Monday, a handful of small point releases (loose dry) were reported on steep slopes on both sunny and shaded aspects. On Sunday, Stevens Pass patrol triggered slab avalanches within the storm snow with ski cuts and explosives. A few of these were big enough to bury a person. Slope testing and snowpack tests consistently showed a good bond at the Feb 19th and Valentine's crust interfaces. On mid to upper elevation shaded, northerly aspects, you may be able to find weak snow near these thin, rough crusts about 2.5-3 feet below the surface.

Regioni coperte