Bollettino valanghe

Mt Hood

Northwest Avalanche Center
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Pericolo valanghe

Tue
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
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

Fluctuating snow levels will create overlapping avalanche problems on Monday. You’ll find the most dangerous avalanche conditions in wind loaded terrain, but don’t ignore more sheltered steep slopes that hold over 6 inches of new snow. Pay attention to signs of warming as the day progresses and don’t ignore obvious signs of instability like cracking or recent avalanche activity. 

Problemi valanghivi

  • Storm Slabs

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

     With over 1.00 inch of precipitation in forecast and fluctuating freezing levels, look for unstable storm snow and reactive wind slabs above 6000 ft. We suspect peak instability will occur during the morning hours and should ease as the day settles out. These slabs will be the largest and most consequential in wind loaded terrain, so give these wind slabs some time to settle out before riding or climbing on steep wind loaded slopes.

    You can trigger avalanches on steep leeward ridges & canyons, on mid-slope convexities, under cornices, or on unsupported slopes in the alpine. Pay attention to cracking, hard-over-soft layering, and stiff wind-textured snow to help you identify areas of potential instability. Simplify your terrain selection if you notice recent avalanche activity or shooting cracks under your skis or feet. 

    (2/3/2024)

    Step it back if you notice signs of instability like this. Use small test slopes or snowpack tests to help you gauge the reactivity of the new and wind-drifted snow.  

    Photo: Joe Dellaporta

  • Loose Wet

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

    Clearing skies and increasing freezing levels will promote a round of small wet loose avalanches involving the recent snow. These won’t be big, but don't be caught off guard in consequential terrain. Expect this wet loose activity to be most prevalent on solar slopes and near rocky, craggy terrain. Look for rollerballs and sticky snow surfaces precursors to larger wet loose avalanches.

    (12/10/2024)

    Rollerballs often preceed wet loose avalanches.

    Photo: Irene Henninger

Avalanche Discussion

This is a messy pattern with fluctuating freezing levels, so be on the look-out for overlapping avalanche problems on Monday. The bulk of the precipitation will fall on 6500 ft snow levels, so you’ll likely find the largest slabs and most dangerous conditions at upper elevations. But don’t underestimate the middle elevations. These elevations will be the most impacted by warming and could be the most susceptible to wet loose avalanche activity and even some storm slab activity depending on how much new snow we pick up. The bottom line is simple on days like this; be flexible with your plans and adjust your terrain to match the conditions you find. 

The 12/17 rain event brought nearly 2 inches of rain to upper mountain elevations. This led to a widespread natural avalanche cycle with numerous D2 to D3-sized avalanches in the canyons around Mt. Hood. This rain event was also responsible for creating rain runnels along many mid and lower-elevation slopes and a slick, widespread rain crust in upper mountain terrain.

If you get out, we could use the observations. Submit an observation here. 

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