Bollettino valanghe

Mt Hood

Northwest Avalanche Center
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Pericolo valanghe

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

In sintesi

Mild temperatures and are helping to heal very firm old wind slabs from the weekend, but their size keeps them on our minds. In some cases, these slabs may be thickest toward the bottom of the slope. In less wind-affected terrain, springlike weather will break down crusts increasing your risk of triggering small wet avalanches in steep terrain.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2.5

    Late Sunday brought a report of a snowmobile-triggered avalanche in the neighboring Cascades West South zone on Mt. St. Helens where the rider was caught and buried over 6’ deep and serves as a reminder of the scale of the slabs that linger may linger in the Mt. Hood backcountry. More information is available here. We recommend keeping these slabs on your radar another day even as most slabs may be losing reactivity. An extreme NW wind event blasted 8" of snow into stiff and very thick slabs Saturday night. Control results with explosives at Mt Hood Meadows yielded three large avalanches on generally E-facing slopes with crowns up to 6-8 ft deep (images in the photo gallery). Slabs were triggered mid-way down or even low on the slope.  Continue to steering clear of steep, smooth and chalky snow or wind-loaded convexities in the terrain, particularly low down in an avalanche path where the eddying winds deposited thick drifts. Given the stiff nature of the slabs, shallow rocky terrain at the edges of these drifts will be the likely trigger points. You can travel safely on wind-scoured slopes (sastrugi), ridges, or slopes less than 35 degrees. 

    (1/22/2023)

    D2-2.5 (large) explosive triggered wind slabs in atypical alpine start zones low on the slope.

    Photo: Mt Hood Meadows Patrol

  • Loose Wet

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

    Wednesday may start with near-freezing temperatures and firm or breakable crust surfaces, but it won't take long for temperatures to soar into the upper 30s and 40s with strong sunshine. Surficial crusts have formed over the last several days in sheltered SW-S-SE aspects where unconsolidated snow existed early in the week. You should become wary when these crusts break down. You can trigger small wet loose avalanches on slopes 35 degrees and steeper. If you encounter rollerballs, wet avalanches may originate on the slopes above you. In all cases, adjust your aspect and seek cooler, shaded slopes.

Avalanche Discussion

Temperatures above freezing to at least 7300 ft on Sunday, likely forming crusts on some aspects. Expect warm temperatures and light winds to allow snow surfaces to soften quickly on Wednesday.

NW winds have been strong at times through the first half of the week. However, there's not much snow that hasn't been affected by the wind on Mt. Hood after the extreme wind event last weekend. Early in the week, you could still find less wind-affected snow below 5500 ft.

Surface hoar was observed in some locations prior to Saturday's storm, however, the intensity of the winds with Saturday night's system likely destroyed any weak grains prior to burial.

Connect with us and your backcountry community by submitting an observation. 

 

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