Bollettino valanghe

Mt Hood

Northwest Avalanche Center
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Pericolo valanghe

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

In sintesi

Don’t let clearing skies and sun fool you into thinking steep, drifted terrain is safe. Recent storms have deposited 1-3 foot thick wind slabs that may remain reactive to the weight of a skier or climber above the rain/snow line. Ease into terrain slowly and consider avoiding steep slopes that appear freshly wind loaded. 

Problemi valanghivi

  • Wind Slabs

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

    You can trigger 1-2 foot thick wind slabs along leeward slopes above 6500 ft. Pay attention to where wet snow transitions to dry, and that will be about when you will want to start thinking about wind slabs. Decreasing wind speeds and minmal weather inputs should help wind slabs become more stubborn, but that may not be true in all terrain features. 

    Use visual clues like blowing snow or textured drifts to help you identify where the wind has been at work. You can typically find these slabs on the lee sides of ridges & canyons, below rock and cliff bands, and on the break-over of steep un-supported features. Monday will be a good day to use small test slopes and snowpack tests to help you gauge the reactivity of the recent wind-drifted snow in smaller terrain features. However, these small test slopes don't always paint the full picture for the denser hard slabs you may find lurking on larger slopes in the alpine. In these areas just consider building in wider margins and avoiding slopes that may harbor these larger, stiffer slabs above 7000 ft. 

    Shooting cracks, drum-like-sounding snow, and recent avalanches are all good reasons to head for lower-angled slopes or wind-scoured aspects. 

    (3/13/2024)

    Blowing snow may not be obvious on Monday, but wind stiffened snow should be. Small test slopes like this can provide valuable information. 

    Photo: Joe Dellaporta

  • Loose Wet

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

    Rain on snow has wettend the snowpack below 6500 ft. The initial wet loose cycle has likely run its course, but still be on the lookout for lingering wet snow instabilities. Rollerballs, pinwheels, and deep boot penetrations are good reasons to default to less steep terrain. 

    (1/5/2025) Photo: Katie Pistello

    Rollerballs are often a precursor to wet loose avalanches. 

Avalanche Discussion

My biggest question for this forecast is where the current rain/snow line sits and the potential reactivity of the lingering wind slabs.  We suspect the rainline is somewhere around 6500-7000 ft, but we’re not sure since poor visibility limited visual observations on Sunday. With wind speeds notching down and clearing skies, we suspect wind slabs will be more stubborn to human triggers, but this may not be the case in all terrain features. This will be a good reason to ease into the terrain slowly and build wider margins as you gain elevation on Monday. Look for more challenging and potentially more dangerous conditions on the upper mountain. We have received significant precipitation this week, so this likely resulted in several feet above the snow line. 

On Sunday, the Mt Hood Meadows Pro Patrol reported triggering numerous D2’s in wind loaded terrain above 7000 ft. These slabs broke up 18 inches deep in drifted pockets. They also reported wet snow and a breakable crust within their operational terrain below 6500 ft. 

If you get out, we could use the observation.

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