Lawinenlagebericht

West Slopes South

Northwest Avalanche Center
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Lawinengefahr

Sun
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
2 · Mässig
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Veraltet — dieser Lagebericht ist 4 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

Saturday should be the final day in our recent pattern of snow showers and periods of gusty winds. You are more likely to trigger an avalanche in areas where the breeze has drifted the snow into deeper piles. You may have to avoid those unstable pockets on a different aspect in the afternoon than you did in the morning. 

Lawinenprobleme

  • Wind Slabs

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

    Wind-loaded terrain should once again be the most likely location for you to trigger an avalanche on Saturday. Breezy conditions approaching moderate speeds could impact the zone for much of the day. The wind direction should switch from easterly toward westerly as the day progresses, meaning that you could find freshly building slabs on a variety of aspects. This includes areas where you’re not used to seeing them such as the other side of the ridge or midslope cross-loading. Actively blowing snow, fresh drifts, or changes in the snow depth as you travel are good clues you can use to help identify wind-loaded areas to avoid. Remember that even a small avalanche can be dangerous if you’re in high consequence terrain. If you suspect a slope to be wind-loaded, best to avoid it by seeking out lower angled options.

    (4/11/2022) A small but deep wind slab was triggered by a small cornice fall on this wind stripped slope. The lines below are wind drifts. W, 6400', SS-ACc-D1-R1-S Photo: Dallas Glass

Avalanche Discussion

After receiving another 3-5” of snow around the West South on Thursday night, relatively calmer weather impacted the zone for much of the day on Friday with periods of sunshine and gentle winds. Crystal Mountain Pro Patrol and avalanche professionals at Paradise both reported rollerballing and plenty of tree bombs during the sunny hours, but that the snow never quite reached the threshold to produce wet avalanches. 

This is the nature of our springtime weather. A similar pattern has occurred over the past few days and may continue on Saturday. Waves of precipitation mixed with brief periods of solar input have begun to take their toll on the upper snowpack on slopes that receive direct sunshine. You could find that several thin sun crusts have developed on these slopes, with soft snow between them, making for an upper snowpack crust sandwich. On more open slopes, these multiple subtle crusts may have melded together. Below them, 2-3 feet of generally right-side-up cold dry snow still exists over the prominent 4/8 interface. On shadier slopes, you should find less of a surface crust. Instead, expect to find drier snow available to be transported by the wind or produce Dry Loose avalanches on steeper slopes. We do not anticipate any avalanches failing below the 4/8 crust at this point in time. 

Don’t rule out more sun breaks during the day on Saturday. If you notice rollerballing or new fan-shaped avalanches, wet avalanche potential is increasing and it may be time to head for shadier slopes. As the day wears on, those breaks should lessen and clouds and snow showers should increase, much like in recent days. On Sunday, we may see slightly warmer temperatures and more widespread wet avalanches.

Although our season is winding down, conditions are still stormy and avalanche hazard is fluctuating. We still need you to share information with us by submitting public observations about what you're seeing out there. Thanks in advance!

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