Bollettino valanghe

Mt Hood

Northwest Avalanche Center
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Pericolo valanghe

Wed
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
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In sintesi

Tuesday will be a pleasant day, but don't ignore the thick wind-textured dunes on the downwind side of the ridges. These wind deposits may be harder to trigger, but the resulting avalanche could be large if you get unlucky. As the day heats up, consider moving to shadier slopes as rollerballs start shedding. 

Problemi valanghivi

  • Loose Wet

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

    We expect a good, healthy dose of sun, so be looking for rollerballs and pinwheels on slopes that point south. These wet point releases aren't likely to grow that large, but could entrain most of the new snow above the early February crust (EFC). You'll want to move to shadier slopes once you notice sticky surfaces or rollerballs shedding, as these are signs that larger wet loose avalanches could follow. 

    (2/10/2024)

    Move to more shaded aspects once you notice rollerballs like this. 

    Photo: Joe Dellaporta

  • Wind Slabs

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

    Mt Hood has seen over 24 hours of strong W- SW winds that have drifted new snow into dense slabs 1-2 ft thick. These slabs will range in hardness and sensitivity based on elevation. Look for firmer, stiffer slabs in more exposed areas above 6500 ft. These dense hard slabs could pack a punch if triggered.  At middle and lower elevations, you'll generally encounter softer slabs that may give you more feedback, like shooting cracks, but could be easier to trigger - especially during the morning hours. However, as the day progresses, these slabs should gain strength and become more stubborn. While less likely, some slabs could propagate widely if they rest on surface hoar or facets on a crust. 

    Look for these slabs on NE-E-SE aspects. If you're looking for a wind slab, you can typically find one on the leeward side of a ridge or moraine, below cornices, or adjacent to rock and cliff bands. Winds will be light, so use surface clues like textured, rippled snow to help you identify wind-loaded pockets. As you travel, tweak small test slopes or dig quick pits with your poles to see how these wind slabs are bonding to the old snow surface. Hard over soft layering and shooting cracks are signs of instability that should help you default to less wind-exposed terrain. 

    I found plenty of evidence of slabby, wind-drifted snow along ridge lines on Monday. Look for textured snow like this to help you identify wind-loaded aspects. 

    Photo: Joe Dellaporta

Avalanche Discussion

Tuesday is shaping up to be a beautiful day for backcountry travel in the Mt Hood zone. Enjoy the sunshine since we'll be heading into a more active weather pattern come Wednesday. With this, look for a spike in avalanche danger in the coming days. 

On Monday, observers reported heavy drifting along ridgelines in Heather and Clark Canyons. They reported fun but "slabby" ski conditions. The Mt Hood Meadows Pro Patrol also reported strong W winds and triggered small, soft slabs (D1) with explosives in the wind drifted snow. 

Earlier this week, NWAC forecasters traveled on the south side near Timberline and found a widely propagating avalanche in the lower Salmon River Canyon (SE aspect, 6300 ft). This avalanche was pretty shallow (6-12 inches, but propagated surprisingly wide. The crown was partially filled in, so the avalanche may have occurred Friday. In a profile on an adjacent slope, the culprit layer was identified as buried surface hoar 4-6 inches below the snow surface. It was easy to spot with snowpack tests. The forecast team is unsure how widely distributed this weak layer is across the zone, but we suspect the most likely places you may find it will be on shaded slopes above 5000 ft moving forward. 

The lower elevation snowpack has endured a beating after last week's warm-up. Below 5000 ft you'll encounter plenty of shallowly buried objects, open creeks, and rough surfaces. 

Your avalanche, snowpack, or weather observations are extremely valuable to the forecasters at NWAC. Help create a more accurate avalanche forecast by submitting your observations here. 

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