Bollettino valanghe

Mt Hood

Northwest Avalanche Center
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Pericolo valanghe

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

Slabs were easy to trigger on Sunday and will remain dangerous and reactive on Monday, particularly during the morning hours. Most slabs will be fast-running and 6-12" deep, but at upper elevations, they will be harder to steer around and some will be large. Ease into the terrain and avoid wind-loaded slopes steeper than 35 degrees.

Problemi valanghivi

  • Wind Slabs

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

    Through Sunday evening, moderate to at times heavy snowfall brought 8" of snowfall by Sunday evening. We're expecting storm totals in the 10" range. Moderate to strong winds peaked Sunday afternoon but should continue to transport snow onto lee slopes through Friday night. NWAC forecast Joe Dellaporta found touchy slabs near treeline on Pea Gravel Ridge, with propagating cracks and fresh sharp cornices serving as a reminder before he jumped on and intentionally triggered small avalanches on test slopes. While the active wind loading may not be present on Friday, these slabs will take time to heal. You can can also use small wind-loaded test slopes to evaluate how quickly the slabs are healing in your terrain. We expect reactive slabs in the morning that you can trigger on wind-loaded slopes steeper than 35 degrees. By the afternoon, most avalanches might be on steep, unsupported slopes as they become slightly more stubborn. As you ascend into above treeline terrain, expect to find large and well-connected slabs to the lee of ridgelines. These slabs will be more dangerous with a high potential for injury or worse. Large, overhanging cornices may break farther back than you expect along ridgelines and could trigger wind slabs on the slopes below if they fail.

    We have enough snow that you could trigger a storm slab in very steep sheltered terrain, but the cooling trend makes dry loose avalanches more likely. Shallow wind slabs are also possible near exposed features below treeline.

Avalanche Discussion

Winter conditions have returned to Mt. Hood. The current snowpack consists of 8"+ of new snow over wet grains (with a rain crust up to 6600 ft at least on top buried by a dusting of snow on 1/14). Below that, you'll find dry snow with periodic crusts. The crust caps some layers we've been talking about in recent weeks, including the 1/4 surface hoar. While this layer was still present on 1/15 in sporadic wind-sheltered terrain such as on Vista Ridge, it is not currently believed to be a cause for concern given the strengthening bridge of the rain crust above it. 

Focus your attention on the new snow above the crust and use the images below to remind yourself how touchy the slabs were on Saturday. Don't get complacent because you've seen similar situations on Mt. Hood before; these slabs will run faster than you expect.

If you're out on the extended weekend, let us know what you see and submit an observation - any information is useful.

 

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