Bollettino valanghe

Stevens Pass

Northwest Avalanche Center
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Pericolo valanghe

Sun
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato
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In sintesi

Expect dangerous avalanche conditions as natural wet avalanches will be likely. Some of these could be large enough to bury or injure you, and they could come down from overhead terrain. You will be able to trigger wet avalanches wherever you find rain falling on previously dry snow. 

Problemi valanghivi

  • Loose Wet

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

    Avoid traveling or stopping under steep overhead terrain, especially below rock slabs and cliffs where large wet avalanches could come down from above. Carefully assess small test slopes before venturing onto any terrain over 35 degrees. If you find wet snow that slides easily, or rain water reaching deep into the snowpack, stick to lower-angle slopes.

    We expect natural avalanches to occur by morning with activity peaking by late morning. At middle and upper elevations you could see wet slab or glide avalanches, and even loose wet avalanches big enough to injure our kill you. Any wet avalanche type will be most prevalent where the snow surface stayed dry through Friday, which includes west through north through east aspects.

     

    (3/31/2024)

    An example from last season of a large wet loose avalanche that started in very steep rocks and cliffs.

    Photo: Katie Warren

  • Wind Slabs

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

    You may be able to trigger avalanches in wind drifted snow on leeward sides of ridges at upper elevations. Look for actively blowing snow and steer around drifted pillows below ridges.

    Precipitation could shift to snow around mid-morning at upper elevations. After this shift, gusty west to southwest wind could form fresh slabs of snow. 

Avalanche Discussion

A wet storm will move in late Friday night, bringing rain to the zone before switching to snow during the day on Saturday. We expect enough snow to fall to maintain dangerous conditions through the weekend. Our estimates are about 2/3rds of the precipitation that falls before 4p Saturday at middle elevations will be rain, however, that could easily change. 

An NWAC forecaster was on Stevens Pass on Wednesday. Snow depths near 5000ft averaged 3-4ft, with slightly less snow on southern aspects. The snowpack was holding up well above the inversion, despite temperatures in the mid 40°F's. Southern aspects had a strong, well-consolidated snowpack with a thin melt-freeze crust on the surface. It may take a decent amount of rain to break down this crust. On north aspects the previously cold, dry, layered snowpack will be become reactive more quickly, once rain begins. A layer of weak layer, about 5 inches below the surface and a mid-pack facet crust layer are both be suspect for deeper wet avalanches. The good news is that the rain should destroy the weak surfaces (facets and surface hoar) that have been found on a range of slopes. You can expect challenging travel conditions with many rocks, trees, and holes still exposed in our shallow snowpack and breakable crusts on southern slopes. 

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