Bollettino valanghe

Mt Hood

Northwest Avalanche Center
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Pericolo valanghe

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

Early season conditions, extreme storminess, and rising avalanche danger will make safe travel more challenging than the danger rating reflects on Saturday.  You can easily trigger a wind slab on any wind-loaded slopes steeper than 35 degrees with continuous coverage. Avoid these areas, recognizing that early-season coverage will increase the risk of trauma.

Problemi valanghivi

  • Wind Slabs

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

    The first major storm of the season arrives Friday night and Saturday with strong to extreme winds building potentially large wind slabs on steep, exposed slopes at all elevations. Firm, punchy, or cracking snow surfaces provide ample evidence for reactive wind slabs in your terrain. Avoid all wind-loaded slopes steeper where you find continuous snow. These areas will be far more prevalent in the upper part of the above treeline band but extend to a heightened danger on terrain features such as wind-loaded gullies near and below treeline. In wind-sheltered locations below treeline, you may have enough coverage in some areas for the storm snow to fail as small storm slab.

Avalanche Discussion

Mt. Hood picked up approximately 2 ft of snow since temperatures cooled early Wednesday morning. That snow fell primarily on dirt. NWAC forecasters and Pro Observers were in the Timberline area both Thursday and Friday. They reported similar conditions on both days. Several days of Moderate winds with occasionally strong gusts stripped snow off of many terrain features near and above treeline. The snow deposited in ravines and canyons where observers could easily trigger a shallow wind slab. NWAC forecaster Andrew Kiefer encountered challenging travel around little zigzag canyon on Thursday.  Below treeline, there was not enough snow to ride or warrant an avalanche hazard on Thursday, but that coverage was increasing on Friday.

A major storm will rapidly ramp up the avalanche danger on Saturday. Expect 1-2 ft of fresh snowfall through Saturday afternoon. Extreme winds will continue to strip exposed slopes, building larger slabs in canyons, gullies and on generally east-facing slopes. Recognize that your danger of triggering an avalanche on any slope with sufficient coverage might be higher than you expect given the danger rating. This is because travelers will be forced to recreate on the very same slopes where you can trigger a wind slab.  You can minimize the avalanche and early season hazards and still recreate safely by choosing lower angle slopes (less than 35 degrees) with continuous snow coverage.

Uphill travel reminder: Check in with your local ski area this weekend regarding terrain access and parking updates. Closed ski areas often share a similar snowpack and avalanche hazard as the surrounding backcountry. You may also encounter other hazards like active avalanche mitigation, unmarked obstacles, snowmobiles, groomers, and other heavy equipment as ski areas prepare to open. Be prepared to make your own assessments and handle emergency situations.

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