Bollettino valanghe

West Slopes North

Northwest Avalanche Center
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Pericolo valanghe

Wed
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

A potent storm will move in overnight bringing another round of heavy snow and strong winds. Anticipate poor visibility, stormy conditions, and elevated avalanche danger to start the morning. Avoid steep, open slopes and start your day in sheltered areas until the storm winds down.

Problemi valanghivi

  • Storm Slabs

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

    You are more likely to trigger a fresh slab on slopes accumulating wind-drifted snow. But the quantity of new snow means you should assess stability in sheltered areas as well. Lower elevation areas should have less new snow. Blowing and drifting snow will show you which slopes hold thicker, more sensitive slabs.

    Use a ski pole or simply dig down with your hand as you gain elevation and change aspects to look for differences in new snow depth and stiffness. More snow, denser snow, or bigger differences in hardness between layers?  More likely you will trigger an avalanche on similar slopes that are steep enough to slide.

    Look for instability using test slopes, hand shears, and other simple tests. Shooting cracks are a sign you could trigger an avalanche if you head onto a steep slope. When in doubt just stick to simpler, sheltered, lower-angle terrain.

    Steep, freshly wind-loaded terrain like this is where you would most likely trigger an avalanche on Tuesday.

     

Avalanche Discussion

Observers reported a general lack of dry snow at mid and lower elevations on Monday. It was easy to get wet snow moving down the hill and rollerballs were observed below steep rocky or treed terrain. Expect similar conditions on Tuesday. Be ready to navigate wet snow instability, especially if the snow level creeps up higher than forecast. Avoid travel on or immediately below steep slopes where you see fresh rollerballs and new avalanches, or simply find wet, mushy snow.

Backcountry reports also mentioned poor visibility for the majority of the day in the Baker BC. Sticky snow at mid-elevations limited wind transport. There was 12-24” over 12/21 crust, which is starting to freeze up and become supportable under the new snow. A good bond between the crust and the layer above has been reported from mid-elevations. You may find a firmer, slicker crust below the new snow as you gain elevation. 

Avalanche control work produced a handful of large avalanches in upper-elevation, wind-loaded terrain. This is a telling sign that you could find greater avalanche danger as you gain elevation - or travel farther east in the forecast zone - into areas where there is simply more cold, dry snow and stronger winds to drift it onto leeward slopes. Information is limited from upper elevations, so take the time to assess stability if heading up there in the next few days.

Less new snow, but also fewer clouds, were reported from the north side of Mt. Baker above Glacier Creek. Signs of wind-drifted snow were limited to higher alpine terrain and no signs of instability were observed. This observation - in comparison with those from the Baker BC - is a classic example of the variability of weather, snowpack, and avalanche factors across a single forecast zone. 

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