Bollettino valanghe

Mt Hood

Northwest Avalanche Center
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Pericolo valanghe

Sun
Alta quota
1 · Debole
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole
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In sintesi

"Low danger" does not mean "no danger". Clouds will compete with mild temperatures over the strength of the surface crusts on sun-exposed slopes and potential moistening of cold N aspects. If you find sticky surface snow or begin punching through a crust, seek lower-angle terrain or colder frozen aspects.

Problemi valanghivi

  • Loose Wet

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

    Thick surface crusts on some aspects and wind-affected snow at upper elevations may limit the potential for wet loose avalanches. However, a poor overnight refreezes at some elevations could make it easier to break down thinner crusts on isolated aspects. A softening surface crust makes for great riding conditions, but if that crust breaks down and you can break through it, expect loose wet avalanches. Previously dry snow on N aspects could become moist and ripe for triggering a loose wet avalanche. Monitor surface conditions carefully and if you find moist or wet snow you can sink into up to your ankle, then steer around higher consequence terrain and seek colder, firmer aspects.

    (3/27/2021) An example of a classic wet loose avalanche in the Mt. Baker Backcountry. Photo: Zack McGill

Avalanche Discussion

High temperatures were near 50F at 5000 ft Wednesday-Friday. The warm weather and sunshine produced generally small avalanches (D1-1.5) on E-S-W aspects on Wednesday and Thursday, but a solid overnight refreeze Thursday night limited avalanche activity on Friday. Forecast freezing levels remain above 8000 ft through Saturday afternoon. Adding to the mild temperatures, the thickening high clouds Friday night might reflect outgoing longwave radiation back to the surface, helping create a poor overnight refreeze. A low-level inversion may limit this concern below treeline where thick crusts exist on most aspects, making the near treeline elevation band our greatest area of uncertainty. While we expect cloud cover on Saturday to limit the impact of the potential poor overnight refreeze, we have some uncertainty regarding which aspects may soften enough to produce wet loose avalanches. Maintain an eye out for nearby fresh avalanche activity as a warning sign that the snowpack state may be more unstable than forecast. 

Sunday night's storm brought 6-12" of new snow that is generally well bonded to the melt-freeze crust from the weekend. Upper elevation winds reached almost 100mph Sunday evening and likely scoured or compacted the snow in many typical start zones. The wind-compacted snow at upper elevations will be slower to destabilize with mild temperatures. 

During the ongoing Covid-19 pandemic, continue to follow the latest guidance from local, state, and federal health officials. Avoid unnecessary risks that could impact first responders and stress medical resources.  Wear a mask when appropriate, practice social distancing, and consider recreating closer to home.

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