Bollettino valanghe

West Slopes North

Northwest Avalanche Center
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Pericolo valanghe

Fri
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 3 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Strong ridgeline winds will form shallow new winds at mid and upper elevations late tonight and Thursday.   Several inches of new snow offers a welcome refresh for variable snow surfaces.  In areas of the zone that receive less snow and at lower elevations in general, expect challenging travel conditions to persist.    

Problemi valanghivi

  • Wind Slabs

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

    If you are traveling near or below ridgelines look for blowing snow, fresh cornices, and pillowlike drifts to identify wind-loaded areas to steer around.  If you observe shooting cracks, you're likely to trigger a shallow wind slab on nearby steep wind-loaded slopes.  With more available dry snow to move around, be prepared for the possibility of deeper and more consequential slabs in the highest terrain. 

    The good news is that in an otherwise quiet weather pattern, the West North should squeeze out several inches of new snow late tonight through mid-day Thursday.  The flip side is that this new snow will likely be accompanied by strong winds.  The new snow will fall on a mix of surfaces like older and firmer wind-affected snow and surface crusts of various thicknesses/roughness.  In other zones, surface hoar has been widely observed following during cool clear nights.  Mild temperatures and strong winds may have limited surface hoar growth in this zone but it's worth keeping in the back of your head as you leave sheltered terrain.  If you observe slab avalanches releasing wider than expected or from lower angle terrain, dial back your terrain choices. 

    (12/1/2023)

    Example of long shooting cracks on test slopes in wind-drifted areas. Signs of instability like this can help inform your travel choices.  

    Photo: Joe Dellaporta

Avalanche Discussion

Observers on Monday and Tuesday found variable surface crusts and generally safe avalanche conditions.  Windy conditions, mild temperatures and a mix of sun and high clouds on Wednesday likely didn't move the needle very much.  Blowing snow has been observed on the higher peaks in the area during this stretch.  If you're traveling in the backcountry in the West North zone, especially to upper elevations, help us learn more about conditions by submitting an observation. 

Reaching back to our last major storm, over a foot of snow fell Saturday afternoon and night with strong winds. The wind affected nearly all mid and upper-elevation slopes, texturing surfaces and forming wind slabs. On the tail end of this system on Sunday, conditions warmed and snow turned to rain.  Several clear nights have allowed surface crusts to form.  Beneath the crust and especially at mid and lower elevations, you're likely to find moist snow lingering. 

Regioni coperte