Bollettino valanghe

Stevens Pass

Northwest Avalanche Center
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Pericolo valanghe

Wed
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
3 · Marcato
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In sintesi

7a Update: CONSIDERABLE Danger at all elevations due to lower precipitation totals overnight and forecasted wind speeds Tuesday.

 Dangerous avalanche conditions will continue on the highest slopes where avalanches will be driven by ongoing snow and wind. Avoid steep slopes where the wind forms deeper drifts of snow near and above treeline. You can trigger avalanches in the new snow at mid and lower elevations, especially on sun-exposed slopes or where you find wind-drifted slabs and hard over soft layers of new snow.

Problemi valanghivi

  • Wind Slabs

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

    Avoid slopes 35 degrees and steeper, especially where the wind drifts stiffer slabs of snow. Stick to areas that are sheltered from the wind, less than 35 degrees, and well out from under steep slopes. Avoid being on or under cornices. Fresh avalanches, cracks shooting through the snow, stiffer snow, and active wind transported snow are all signs that you should avoid avalanche terrain.

    There may still be a chance for natural avalanches on leeward slopes. Some avalanches could reach size D2.5-3 or big enough to break trees or bury a car. Cornices have built rapidly and could fall and trigger slides, especially if the sun shines on them. You may still be able to trigger avalanches at lower elevations. Even in wind-sheltered terrain, you can trigger avalanches in the storm snow. Use quick tests, small test slopes, and look for hard over soft layering. New snow could slide easily on older crusts or moist layers buried in the past week.

    (4/4/2022)

    Wind drifts, 3.5 feet deep, in an open area below treeline. SE, 4500ft

    Photo: Katie Warren

  • Loose Wet

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

    If the sun shines on steep slopes, expect to see natural wet avalanches. If they gouge through all of the recent snow, they could become large and dangerous. Indicators that wet loose avalanches could occur are prolonged breaks in the clouds, moist snow surfaces, wet snow falling from trees, and rollerballs. If you see this or wet avalanches, move to more shaded, northerly aspects or slopes less than 35 degrees.

    The showery nature of this storm could create moments of clearing or thin clouds throughout the day. The best chance for prolonged sun and clearing looks to be after 11am. Expect more significant clearing east of Henry Creek or Rock Mountain.

    (4/1/2022)

    Skiers triggered wet loose avalanches on the SW face of Lichtenberg on 4/1.

    Photo: Public obs

Avalanche Discussion

An intense storm is winding down through the Cascades. As of Monday evening roughly 2.5 feet of snow accumulated (at 5,000ft) at Stevens Pass in 24 hours. Snow totals could reach over 3.5 feet by late Tuesday. Triggering avalanches in the storm snow on wind-sheltered slopes below treeline remains possible. Snow totals are less at lower elevations. Below 3,500ft, may not be enough for significant avalanche hazard.

On Monday, forecaster Katie Warren and I traveled to the Skyline Lake area. By 12:30pm we found 2 feet of accumulation, with the storm snow consistently cracking or breaking on an interface of hard-over-soft storm snow 12-18" below the surface. The snow had an "upside-down" feel underfoot, meaning it felt heavier near the surface than below. We triggered 3-4 small avalanches (see video below) that initially broke at this interface and ran on the old snow surface. Winds were strong to extreme with intense blowing snow even in open areas below treeline. If you're in the mountains, submit an observation and let us know what you see.

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