Bollettino valanghe

West Slopes Central

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 4 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Strong winds plus light to moderate snowfall will increase the avalanche danger Thursday. Steer around steep terrain where the wind is depositing snow and building new slabs. Very stormy conditions in the morning could make backcountry travel difficult.

Problemi valanghivi

  • Wind Slabs

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

    Expect to see active wind loading and new slabs building on lee slopes. Forecast wind speeds are strong enough that you might see them farther down slope than usual. The key observation will likely be figuring out which slopes actually hold wind slab. In the thick of the storm - if you can see at all - blowing snow will point out which slopes you should avoid. After it calms a bit you can use other clues like the rimed trees and rocks, or scoured surfaces to figure out where wind slabs might lie in wait. Danger will be higher in areas that experience heavier snowfall throughout the day. Default to even simpler, less exposed terrain if this is the case.  

    Blowing snow, firm and textured snow, and cornice formation are all evidence that wind slabs are likely to be forming on lee slopes. Photo: Dallas Glass

Avalanche Discussion

An intense but fast-moving storm crosses the Cascades tomorrow. Though forecast precipitation amounts are light, most new snow should fall within a few hour period in the morning. Winds will ramp up this evening and stay strong through midday. Look for calmer conditions in the afternoon. 

With few snowpack observations in West Central so far this winter, we need to look to other zones to see the larger pattern  A combination of crust and facet layers is found up and down the west slopes, buried by 2-4’ of recent snow in most areas. To the south, no human triggered avalanches at these layer interfaces have been reported. The same layers appear to be rounding and gaining strength. 

To the north is a slightly different story with a single large, deep avalanche in the middle of a very popular area triggered by a rider lower on the slope. While this event is thus far an outlier, it is also a reminder that we have an early season snowpack built in a period of colder than average temperatures. Keep this in mind and take the extra time to investigate and get a feel for the snowpack where you travel. Information is sparse, the zone is big, and snowpack variables can and will differ from one valley to the next.

Wednesday was a quiet day in the mountains with no significant changes or observations reported. A slight temperature increase - especially at lower elevations - settled the snowpack another inch or two. Periods of moderate wind the last few days have filled in old tracks but didn’t create much in terms of new wind slabs.

Regioni coperte