Bollettino valanghe

West Slopes North

Northwest Avalanche Center
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Pericolo valanghe

Fri
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato
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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 and a burst of heavy snowfall could make for dangerous avalanche conditions. Natural avalanches are possible Thursday morning when the storm is at its peak - a good time to limit your exposure to avalanche terrain. Very stormy weather could make backcountry travel difficult.

Problemi valanghivi

  • Wind Slabs

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

    Thursday morning will not be the time to tiptoe around wind slabs in avalanche terrain. It'll be best to just avoid steep terrain where the wind is depositing snow and building new slabs. Expect to see heavy snowfall and intense wind loading. Forecast wind speeds are strong enough that you will probably find wind transport occurring in all terrain. If you are out and about, take your time figuring out which slopes actually have new slabs. In the thick of the storm - if you can see at all - blowing snow will simply point out which slopes you should avoid. After it calms a bit you might need other clues like the rimed trees and rocks, or scoured surfaces to figure out where wind slabs might lie in wait. Very strong winds may just create a patchwork of slabs in most areas that you can see if weather conditions improve in the afternoon.

Avalanche Discussion

An intense but fast-moving storm crosses the Cascades tomorrow. Most new snow should fall within a few-hour period in the morning and this is when avalanche danger should be the highest. Winds will ramp up this evening and stay strong through midday. Look for tapering snow showers  and calmer conditions in the afternoon. 

Since the weekend there were no reported avalanches in recent wind slab layers. One unusual avalanche warrants more attention. It was larger, notably deeper (4’ at the crown), and released above the rider who triggered it. The weak layer was observed as small faceted grains above a hard crust buried on Nov 25th. While definitely an outlier - no other avalanches of this kind have been reported on the west side of the Cascades - it’s still a large, deep avalanche in the middle of a very popular area triggered by a human. It is also a reminder that we have an early-season snowpack built in a period of below average temperatures. Simpler terrain is the easiest way to reduce uncertainty about snowpack, especially during active loading.

Wednesday was a quiet day in the mountains with no significant changes or observations reported. A slight temperature increase 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