Bollettino valanghe

West Slopes Central

Northwest Avalanche Center
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Pericolo valanghe

Sat
Alta quota
3 · Marcato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 4 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Avalanche danger will increase with snowfall, strong winds, and a rise in snow levels. Stick to simpler, lower-angled terrain to reduce the likelihood of triggering an avalanche. Heavy rain in the last week exposed creek holes, rocks, and other features that could injure the unwary.

Problemi valanghivi

  • Storm Slabs

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

    Up to a foot of new snow along with warming temperatures should build sensitive slabs on all aspects. Strong winds will make slabs thicker and more reactive in wind-loaded areas. Avoid steep slopes where you witness active wind transport. Assume a higher level of danger during periods of intense snowfall. This is most likely around the Mountian Loop during convergence zone enhanced snow showers.

    Shooting cracks and recent avalanches are obvious signs that conditions are becoming less stable. You can also just keep tabs on new snow layering with hand shears or stomping on short, steep slopes and wind lips. These tests are easy to do on the move and give instant feedback about new snow stability. Adjust your plan based on your observations and move to simpler terrain as signs of instability increase.  

    If traveling at lower elevations, look for signs of wet avalanche activity and even small avalanches as snow switches over to rain. 

    (12/20/2022)

    An example of a denser slab easily sliding on slightly weaker snow below.  Simple tests like shovel tilts, hand shears and just stomping or cutting across short, steep, no-consequence, slopes help gauge the bond of new snow layers.

    Photo: John Minier - Baker Mountain Guides

Avalanche Discussion

Observers in West North found a foot of new snow developing a good bond to the rain-affected layer below. Wind slabs and other signs of active or recent wind transport were evident in exposed areas. No signs of instability were reported until Thursday afternoon when increasing winds built small but fragile new slabs. No significant avalanche activity was reported since the rain event last weekend. Stronger winds and greater wind transport were reported from Snoqualmie Pass. 

The 6-10” of rain from December 23rd through the 27th reshaped the winter landscape at and below the snow surface. The existing snowpack was basically reset as a deep layer of wet grains now topped by the most recent snow. A crust is forming at the wet snow layer but it’s generally unsupportable without floatation.  

Large creek holes and other oddly shaped terrain features opened up. Rocks and other objects melted out and were then barely covered with new snow. Frozen, chunky debris - from the natural avalanche cycle early in the rain event - is found in most run-outs. Use caution in poor visibility and when entering rollovers and other undulating terrain features. 

 

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