Bollettino valanghe

Stevens Pass

Northwest Avalanche Center
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Pericolo valanghe

Mon
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

An avalanche warning has been issued for the neighboring East Central Zone where very dangerous conditions exist. Anticipate rising hazard throughout the day as additional loading from new snow and wind increase the size, depth, and likelihood of avalanches. Steer around wind loaded slopes 35 degrees and steeper at upper elevations, and use caution as facets on an icy crust underlying recent snow remains a good sliding surface for avalanches. 

Problemi valanghivi

  • Wind Slabs

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

    If you're traveling on the eastern boundary of the zone check out the East Central forecast, where we've issued an Avalanche Warning for very dangerous persistent slab conditions. 

    You can trigger avalanches large enough to bury, injure, or kill a person on upper elevation, wind-loaded slopes 35 degrees and steeper. Avalanches could be surprising and propagate widely where they run on shallowly buried facets over a crust. Fresh slabs will grow in size and distribution with new snow and wind. Avalanches will be larger and easier to trigger at higher elevations. Pay attention as you transition into wind affected terrain and look and feel for sudden changes in snow surface texture and hardness. Fresh slabs rest atop slick and variable surfaces and even weak, sugary snow. Look for obvious signs of instability like recent avalanches, shooting cracks, and collapses, and dial back your terrain choices if any of these red flags are present. You are most likely to trigger a slab on steep slopes below cornices, to the lee side of ridgelines, below rocky outcrops, and in gully features. Carefully assess how recent snow has bonded to old snow surfaces as you travel using hand pits and small test slopes. Seek out lower angled and wind-sheltered terrain to reduce your risk of triggering an avalanche.  

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

  • Loose Wet

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

    Wet avalanches may be easily triggered by riders in steep terrain. These avalanches could entrain enough snow to knock you off your feet, carry you into rocks or trees, or bury you in confined terrain. They may even trigger slab avalanches. Avoid exposure to steep slopes above and terrain features where avalanche debris can concentrate like gullies, benches, and depressions. 

    (1/28/2021) Looking across Hwy 2 at Moonlight/Skyline with a couple of debris piles from recent loose snow avalanche activity. Photo: Charlie Hagedorn

Avalanche Discussion

Observers just east of Stevens Pass, in the East Central zone, have reported triggering dangerous persistent slab avalanches.  While the weak layers and overlying slab are less developed in this zone, a similar snowpack structure can be found. Near Stevens Pass, human triggered avalanches were reported the past few days in wind-affected areas (observation), and even a few small naturals were observed in Highlands Bowl on Wednesday as well as on Tye Peak on Thursday. These avalanches ran on, or just above the old/new snow interface, which is a slippery crust in most areas. Avalanches were small, although new snow and wind are adding up and you could find thicker and more reactive slabs at higher elevations. Carefully assess the snowpack as you travel, especially on the northern half of the compass where you might find layers of weak faceted snow associated with prominent crusts buried by recent and windblown snow. There is uncertainty regarding the distribution and sensitivity of these buried weak layers. Evidence exists but is not always easy to find. Weak snow could be above and below the crusts, or not present at all. The variability may be the biggest challenge, so investigate each slope you plan to ride individually, as what you find in one area may be different from the next.

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.

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