Bollettino valanghe

West Slopes Central

Northwest Avalanche Center
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Pericolo valanghe

Wed
Alta quota
2 · Moderato
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

Light snow and moderate winds will give the mountains a bit of a refresh on Tuesday. Lookout for and bypass steep terrain with recently wind drifted snow to limit the chance of starting an avalanche. 

Problemi valanghivi

  • Wind Slabs

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

    While avalanche danger from wind slabs shouldn’t increase with a few inches of snow and moderate winds overnight, it won’t exactly go down either. Older wind slabs from the weekend were observed as becoming unreactive. Small new slabs will continue to form until winds become calm in exposed terrain or there is no snow available for transport.

    Track the depth of new and wind drifted snow to find areas where fresh wind slabs developed. Stomp on wind drifted features to get a read on wind slab reactivity. Evaluate the bond of wind slabs before committing to steep terrain - or just find a lower-angled line around areas like convex rolls where you are more likely to trigger one.

    (1/23/2023)

    Shallow wind slabs triggered in steep terrain Monday. 

    Photo: NWAC Public Obs

Avalanche Discussion

Observers on Monday found recently wind affected snow and shallow, fresh wind slabs near and above treeline. Strong winds and snow transport were noted at Stevens and Snoqualmie Pass. In West North the old/new snow interface was found 6” down in wind sheltered terrain. Few signs of buried surface hoar or facets were found but the interface in question still produces moderate results in formal and informal testing. Still, the pattern of avalanche activity currently doesn't show much of a problem. Sun breaks didn’t provide nealry enough warming on solar aspects to produce wet loose avalanches in observed terrain.

Most avalanche observations on the west slopes revolved around shallow wind slabs. They tended to be small and 8" deep or less. To the north reported avalanche activity consisted of a human triggered avalanches (to D1.5) on very steep, unsupported features in wind loaded terrain (north aspects @ 5000' and 5100'). 

Late Sunday brought a report of a snowmobile triggered avalanche on Mt. St. Helens where the rider was caught and buried over 6’ deep. Rescuers were able to successfully extract the rider and no significant injuries were reported. More information is available here.

 

Regioni coperte