Bollettino valanghe

East Slopes Central

Northwest Avalanche Center
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Pericolo valanghe

Tue
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 6 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Strong winds and a few inches of fresh snow will create reactive wind slabs near and above treeline. Look for signs of drifting snow and feel for strong over weak layering as you travel. Steer around drifted features on steep slopes, especially if finding signs of instability such as shooting cracks. 

Problemi valanghivi

  • Wind Slabs

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

    A few inches of new snow and fresh westerly winds will create shallow slabs near and above treeline in exposed locations. These may be thicker and wider the higher you go. Look for snow surface texture that indicates recent slab development, such as rippled and wavy surfaces. Check for signs that you could trigger an avalanche such as shooting cracks and feeling for punchy snow and hollow sounding drifts. Steer around the edge of cross-loaded gullies, unsupported roll-overs, and other drifted features on steep slopes.  In the Wenatchee Mountains and areas on the eastern edge of the zone with a shallow snowpack, fresh windslabs have the potential to step down to deeper weak layers. 

    Cornices may be large from the recent storms. Give them a wide berth and make sure to keep your distance by staying off of, and out from underneath these overhead hazards.  

    Example shallow wind slab.

  • Persistent Slabs

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

    Large and surprising avalanches have become less likely to trigger, but are still not impossible. The snowpack structure still harbors weak, old snow layers near recent crusts and near the ground, but time has helped decrease its reactivity. The most likely place to trigger a persistent slab would be in the Wenatchee Mountains, and anywhere with less than 5ft of snow on the ground. Check for weak, sugary snow associated with thin crust layers, or near the ground as you travel.

    The majority of recent avalanches on these layers have been on north through east aspects, and above 6,000ft. Look for cracking or whumphing as you move through terrain. Search out supported terrain, staying off of unsupported and convex rolls, especially on north and east above 5,500ft. Make sure to regroup well away from any steep slopes.

    Near the crest in areas such as the Teanaway, Salmon la Sac, Icicle, and valleys above Lake Wenatchee, you may find a stronger, deeper snowpack. 

    (1/6/2021) Explosive triggered hard slab avalanche at Mission Ridge, NE, 6300ft. Photo Jake Larson

Avalanche Discussion

It appears that avalanche activity has tapered away, until the next series of storms. Expect avalanche danger to begin ramping up with fresh snow and strong winds on Monday. The atmospheric river begins to make landfall Monday night, and by Tuesday we'll be looking at High danger with rising snow levels and heavy precipitation.

A quick recap of recent avalanche events leading up to, and from this weekend: 

Saturday- A skier triggered a slab and went for a ride above Marion Lake (check the obs page for details-to be posted). Other skiers intentionally triggered a shallow windslab on a north facing slope at 7,200ft above Eightmile Lake.

Friday- A skier triggered a D2 near Naneum Ridge, and Mission Ridge Ski Patrol triggered a small slide with explosives that stepped down to weak snow near the ground. These were on northerly aspects right around 6,000ft.

Wednesday- Natural D3 observed off of Diamond Head near Blewett Pass. Mission Ridge Ski Patrol triggered a couple of wide D3 hard sabs that ran on old snow near the ground with explosives.

During the ongoing Covid-19 pandemic, continue to follow the latest guidance from local, state, and federal health officials. Avoid unnecessary risks that could impact first responders and stress medical resources. Wear a mask when appropriate, practice social distancing, and consider recreating closer to home.

Regioni coperte