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
1 · Debole
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In sintesi

Recent wind loading has built slabs that will be reactive to human trigger on Tuesday. Slabs sit above a crust/facet interface with the potential to produce a large and widely propagating avalanche. Steer around steep panels of wind-loaded snow, particularly beneath recently formed cornices.

Problemi valanghivi

  • Wind Slabs

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

    Wind slabs will be more reactive and potentially large at upper elevations.  At middle elevations, they will be smaller and easier to steer around. Well-developed 1 mm facets exist at the early February crust interface, which may have 6" of snow above it by Tuesday. E winds on Sunday shifted to the SW Monday afternoon and overnight, redistributing the snow that fell over the last few days. Therefore, slabs may be reactive on any aspect. Any slope with wind deposition (more than 6" of snow) should be treated as a potential slab that you can trigger on a slope steeper than 35 degrees. Less wind-affected snow may mask the slabs, but you should identify. Rounded bulges of snow, and slopes below recently formed cornices should be treated with suspicion. You're getting into the danger zone in areas of firmer deposits where you have to punch through with your pole or probe to touch the crust. Such deposits could fail on lower-angle slopes where the slope steepens below you.  When in doubt, stick to scoured or wind-protected terrain.

     

    (2/2/2024)

    Small shooting cracks in shallow pockets of wind-drifted snow provide your early warning before you encounter deeper deposits.

    Photo: Joe Dellaporta

Avalanche Discussion

Observers reported 4" of snow at 6600 ft as of Monday afternoon, and with another 2" of snow on the way, expect 6" average snow depths atop the stout early February crust. Anticipate that a crust/facet interface could exist on any middle and upper elevation slopes and aspects unless winds have scoured the snow down to the early February crust. E winds on Sunday created  touchy, human-triggered wind slabs. Slabs were likely gaining size on Monday with additional snowfall and ridgeline winds shifting from SE to SW as they increased into the 15-20 mph range. Snow lines rose up to around 5000 ft by late Monday, so expect another surface crust to form at the top of the 2" or so of snow that formed at ski area bases.

This surface crust should limit the potential for wet loose activity at lower elevations on Monday, but less wind-affected middle-elevation snow surfaces could warm up and destabilize. Reduce your exposure to steep, SW-S-SE slopes experiencing direct sunshine if you find more than 4" of snow above the crust. Rollerballs and snow shedding of trees, rocks, or cliffs give you a final reminder.

The snowpack has transformed over the past week with several inches of rain and warm temperatures. Temperatures returned closer to seasonal norms, but we're left with a more variable snowpack. We lost significant snow at lower elevations, leaving us with many open creeks and shallowly buried obstacles to avoid. Fortunately, middle and upper elevations have held more snow. If you head into the mountains, travel cautiously, as you may encounter new hazards (rocks, open creeks, etc) that weren't present last week. 

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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