Lawinenlagebericht

Stevens Pass

Northwest Avalanche Center
Auf der Karte ansehen

Lawinengefahr

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

Kernpunkte

Use extra caution ascending into upper-elevation terrain.  Identify and avoid steep features and slopes holding recently wind drifted snow. Some afternoon sun could produce a round of small wet avalanches,

Lawinenprobleme

  • Wind Slabs

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

    Steven Pass might not be as ripe for wind slab avalanches as other zones, but there is just enough snow and wind in the forecast that wind slabs should be on your radar. Between a few inches of loose snow above a surface crust - and a few more inches in the forecast - there isn't a ton of snow available for transport at mid-elevations. 

    It could be a different story as you head up to higher elevations where there is probably no crust capping the uppermost layers. More snow available for transport means bigger, thicker slabs that might also be easier to trigger.

    If the wind is blowing, drifting snow will show you which slopes are loading up. Track changes in snow texture, stiffness, and depth to hunt down fresh slabs if you find calmer conditions. Simple tests like hand shears and small slope cuts can show the bond of wind slabs to the layers below. When in doubt, just avoid slopes holding recently wind drifted snow to reduce the likelihood of triggering an avalanche.

     

    (1/29/2023)

    Wind-textured snow and fresh wind lips are clues as to where fresh wind slab might lie in wait for the unwary.

    Photo: Irene Henninger

  • Loose Wet

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–1.5

    Wet avalanche activity is not guaranteed, but don't get caught off guard if the sun comes out. Keep track of slopes picking up some sun, and look for signs of instability like rollerballs or small wet avalanches. You are most likely to see these below cliffs or steep tree covered terrain.  You can also get wet snow to move down the hill, especially where it's poorly bonded to a crust below.

    (12/9/2024)

    Fresh snow over a crust is a good setup to get some snow moving as it warms up.

    Photo: Katie Warren

Avalanche Discussion

Wednesday appears to have brought some respite from the wet avalanche and also slab avalanche activity reported in recent days. Temperatures stayed below freezing until late afternoon. Moderate ridgetop winds were reported to be moving some snow around but not enough to form fresh slabs. The most notable observation in recent days was this slab avalanche remotely triggered in upper-elevation terrain. While the responsible weak layer is unknown, it's a reminder one can find very different conditions - and avalanches - in the same forecast zone on the same day.

The avalanche picture is a bit varied across the west slope of the Cascades. At the north end of the range, observers reported very strong winds, lots of wind transported snow, and reactive wind slabs on a variety of aspects. The slabs were failing at a thin layer of soft snow above a crust that formed a few days ago on all aspects. To the south, the old (and quite weak) snow surface buried on Feb 13th is suspected as the culprit behind a variety of avalanche activity, including a large natural avalanche in Snoqualmie Pass.

 

 

 

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