Bollettino valanghe

Stevens Pass

Northwest Avalanche Center
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Pericolo valanghe

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

In sintesi

Avoid steep, wind loaded areas and stay alert to changing conditions on Thursday. You could trigger large and surprising avalanches at upper elevations where weak snow sits over a slick crust. Professionals have observed clean and planer failures in the upper snowpack, and we expect conditions to begin to turn dangerous on these layers. 

Problemi valanghivi

  • Wind Slabs

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

    Winds will pick up during the day and begin to redistribute the snow that falls, and snow that is already on the ground. Wind slabs could be shallow, or up to 2ft deep if they run on the crust from mid January. Pillows and wind sculpted drifts are good indicators that a wind slab is present. Stay aware as you travel through light fluffy snow and take notice as it become thicker and heavier.  Watching and feeling for changes in the snow are great indicators for finding wind slabs. Look for cracking and listen for whumphing collapses.

    These wind slabs sit over a crust with weak snow sometimes found just above it. In areas where this exists, you could produce larger and more surprising avalanches. Now is still a good time to dig with your hand or a shovel to check how snow is bonding to this crust as you travel. Plenty of uncertainty surrounds this weak layer and warrants careful evaluation as you gain elevation. For this reason, avoid wind drifted slopes in areas that are steeper than 35 degrees, especially at upper elevations.

    Outside of wind affected areas, loose dry avalanches may run on steep, shaded slopes. Be sure to avoid getting pushed into terrain traps such as trees, or over cliffs with these.

    (1/28/2021) A skier remotely triggered this wind slab (D1) on the east face of Tye Peak near 5200ft Thursday. The crown was 20-25ft across and 6-18 inches deep. Photo: Marc Simonpietri

Avalanche Discussion

We are headed into another storm cycle, and this time Stevens Pass could do fairly well with new snow amounts. Confidence for how this new snow will bond to layers new and old is low, because professionals have observed sudden, planer, and often easy failures with snowpit tests in the upper pack. Weak snow above and sometimes within the crust from January 13th is beginning to become a concern in the zone with added snow and wind loading. Until recently, there hasn't been much new snow or slab over this layer, but we expect that to change in the coming days. If you're traveling on the eastern boundary of the Steven’s zone take a look at the East Central Forecast, where persistent slab avalanches are already a concern.

Under the thicker canopy of the trees, the snow conditions are variable, with icy, bumpy surfaces and plenty of downed trees and branches. Use caution while moving through this lower elevation terrain.   

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