Bollettino valanghe

Mt Hood

Northwest Avalanche Center
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Pericolo valanghe

Thu
Alta quota
4 · Forte
Limite del bosco
4 · Forte
Sotto il limite
3 · Marcato
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Non aggiornato — questo bollettino è scaduto 6 months ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

 A potent storm will overload our snowpack and set the stage for very dangerous avalanche conditions on Wednesday. Natural avalanches will become increasingly more likely as the day progresses. Let the storm run its course by sticking to simple, low-angle terrain without any overhead avalanche concerns. 

Problemi valanghivi

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Very Likely
    Dimensione
    1.5–2.5

    The recipe for natural avalanches on Wednesday is pretty simple:

    • Significant precipitation with 24-hour totals of 2-3 inches (with significantly more arriving Wednesday night).
    • Warming with snow levels pushing up to 5000 ft.
    • Very strong winds transporting large amounts of new snow at middle and upper elevations
    • Heavy dense snow falling on lighter, low density snow from recent days. 

    Expect slabs to be larger and more destructive in wind loaded terrain. But, don’t think you’re safe on more wind sheltered slopes since new snow will fall upside down with the warming trend. Storm and wind slabs will grow in depth as the day progresses and these could easily be large enough to bury or kill a person. As the afternoon progresses into the evening, very large avalanches releasing into the upper canyons won’t be out of the question.

    The travel advice is simple for a day with these types of weather inputs. Avoid being on or under all avalanche terrain - especially as the precipitation and winds intensify.

    (1/6/2024)

    Avalanches have the potential to be destructive, even in more wind-sheltered areas. This large hard slab avalanche from a couple of years ago in the Pea Gravel area occurred during a similar loading event.  

    Photo: Jack Kuenzle

  • Loose Wet

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

    Snow levels are forecast to bump to 5000 ft by the afternoon, so snow will likely transition to rain through much of the lower elevation band. This rain-on-snow may set the stage for natural wet avalanches and these should be easy for you to trigger on steep slopes. Rollerballs, pinwheels, and rain-on-snow are all indicators that you could trigger wet avalanches on steeper terrain.

    (3/19/2025)

    Rollerballs are a sign that the surface is becoming wet and weak. 

    Photo: NWAC

Avalanche Discussion

We’ll likely start the day with considerable avalanche danger, but expect snowpack stability to deteriorate as warming, high winds, and heavy precipitation continue to overload the snowpack. Slab depths will rapidly increase with heavy loading and the upper snowpack may reach its tipping point. If natural avalanches don’t start releasing during the afternoon, they’ll likely occur during the evening hours as another 2-3 inches of water arrive with the warmest part of the storm.

 As of Tuesday, observers have been finding 9-12 inches of low-density new snow over the robust 3/9 melt freeze crust. This stout crust has reduced concerns with deeper weak layers. Moving forward, avalanches will likely fail on this stout crust or above within the new snow. 

 

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