Lawinenlagebericht

Snoqualmie Pass

Northwest Avalanche Center
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Lawinengefahr

Sat
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
1 · Gering
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Veraltet — dieser Lagebericht ist 3 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

Expect heavy snow and increasing potential to trigger avalanches on Friday, particularly on steep slopes at higher elevations. Slick crusts and weak snow surfaces could allow the new snow to slide easily. Most avalanches won't be large, but a ride through rocks, creeks, and other obstacles can increase the consequences. 

Lawinenprobleme

  • Storm Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–2

    Even with the low snow cover, the quick accumulation of new snow will make it possible to trigger avalanches on steep slopes. The most likely areas to trigger a slide are higher elevations that previously held a more continuous snowpack. Look for the red flag signs of instability, such as collapsing or shooting cracks, as a warning to stick to lower angle terrain. New snow will fall on various surfaces, including bare ground. Therefore, adjacent slopes could react quite differently. Shady, steep, open slopes sheltered from the wind may harbor weak snow surfaces, and sunny slopes likely have a melt-freeze crust. Use quick hand pits to see how new snow bonds to the old surface; if it slides easily, avalanches are more likely. 

    Winds will also transport the snow into stiff wind slabs near ridges. These avalanches could be larger and run further. Any avalanche could have substantial consequences if it drags you through rocks or other obstacles.

    (3/25/2023)

    Quick hand pits as you travel can indicate how well the new snow bonds with the old surface.

    Photo: Andy Harrington

Avalanche Discussion

 We're kicking off the daily forecast season to welcome in a much-anticipated storm for this upcoming weekend. 

We are entering this stormy weekend with a thin snowpack, and most lower elevations are still bare ground. Snow becomes continuous at around 3800ft with about 2ft at upper elevations. On Thursday, NWAC forecaster Andy Harrington found just under 2ft of snow at 4900ft near Silver Peak. Andy and the Alpental Patrol reported a snowpack with a mix of crusts and weak snow layers. The snow surface is melt-freeze crust around an inch thick, and Andy found feathery surface hoar preserved in shady, sheltered terrain. In most locations, the west and south aspects are primarily bare ground. 

With the highly variable nature of the current snowpack, it can be tricky to identify which slopes are more likely to avalanche. Adjacent slopes may act differently from each other, so here are a few tips to track what's happening beneath you as you travel.

  • Dig down frequently as you travel. This is particularly important as you change aspects and climb in elevation. 
  • Use your probe or pole to track snow depths and identify areas of thin snow cover where hidden obstacles may lurk. 
  • Use quick hand pits or test slopes to observe how well the new snow bonds to the old surface. If it slides easily, avalanches are more likely. 

You can expect significant snowfall totals throughout the day on Friday, which means avalanche problems could worsen by late afternoon. The new snow will be relatively low density and may not readily form a slab. Therefore, you may see some long-running loose snow avalanches. Small avalanches or just traveling in these low-tide, early-season conditions have high consequences if you impact rocks or other hazards. So, move slowly and cautiously in the mountains until more snow builds up.

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