Bollettino valanghe

West Slopes North

Northwest Avalanche Center
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Pericolo valanghe

Wed
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

Calmer weather should be in store for Tuesday after the latest storm moves on. Steep terrain holding areas of wind drifted new snow will again be the main concern at and above treeline. Use caution on downwind slopes and stick to lower angled terrain where you observe signs of wind affected snow.

Expect greater avalanche hazard near treeline if there is more than 10" of new snow in the morning or if snowfall persists through the day.

Problemi valanghivi

  • Wind Slabs

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

    Wind slab, wind slab, and more wind slab has been the theme for days. Snowfall and strong winds should taper at some point Tuesday, but overnight they will have been hard at work churning out another batch of new slabs. There's a good chance you will find calmer weather and maybe even some sun in the mountains tomorrow. But the fresh slabs - and even some of the day-old ones - could need some time to stabilize on steep slopes.

    Soft new snow might obscure the clues you normally use to identify loaded slopes. Gauge the depth and stiffness of new snow and assess the bond of wind slab layers as you gain elevation. There is a greater chance of triggering a wind slab on convex breakovers or other unsupported terrain features like hanging slopes above or around cliffs. Avoid these features to reduce risk.

    If more snow falls than forecast be ready to find unstable slabs in wind sheltered terrain, especially if there are periods of heavy snowfall. 

    (1/9/2023)

    Cornice testing produced small but reactive wind slabs on a NW aspect in Canyon Creek at 5600'. Fresh slabs grew larger as strong winds continued through the afternoon.

    Photo: Mike Elges - Cascade Mountain Ascents

Avalanche Discussion

Slowly clearing skies could add some sun to a rise in freezing levels Tuesday. Stay tuned into warming conditions and look out for the usual signs of wet loose avalanche activity. There’s a low likelihood of seeing a larger wet avalanche, but it’s worth keeping track of what is going on above you anytime it warms up and there is new snow on the ground.

Active wind loading was the biggest factor Monday afternoon. After a quiet morning, observers in Canyon Creek and the Baker Backcountry found gusty southerly winds transporting recent new snow onto north aspects. Reactive wind slabs could be found in just about any loaded area. Most were small, shallow and intentionally triggered with slope cuts or cornice drops. Some unintentionally triggered avalanches were 1’ deep, possibly pushing D2 in size. Good riding conditions were found in wind sheltered terrain.

Snow totals from the latest storm ranged from 5-10” across West North. Similar amounts are forecast through Tuesday morning but this time with a drop in wind speeds overnight. At lower elevations, new snow rests on a crust formed during mixed rain and snowfall beginning January 5th. Climbing above 5000' there is noticeably less rain crust and up to 2' of snow since the same date. The new snow is observed as bonded to crusts below with instability found only in new snow and wind slab layers.

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