Lawinenlagebericht

West Slopes South

Northwest Avalanche Center
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Lawinengefahr

Wed
Hochgebirge
3 · Erheblich
Waldgrenze
3 · Erheblich
Unterhalb
2 · Mässig
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Veraltet — dieser Lagebericht ist 5 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

On Tuesday, big changes in the weather could create dangerous avalanche conditions. You’ll need to balance recent storm snow problems and developing wet snow issues. Choose terrain where you can easily identify avalanche paths and avoid steep slopes to manage these dynamic hazards

Lawinenprobleme

  • Loose Wet

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

    Mostly sunny skies on Tuesday could result in a big change for the cold and dry recent snow. On slopes receiving direct sunshine, expect the surface to become wet, unstable, and slide downhill. Watch for clues like new rollerballs, the snow falling out of trees, and a sticky surface. All of these observations may act as indicators for loose wet avalanches and will serve as your warning to seek out colder and more shaded terrain. Since the recent snow sits on top of a crust, some of these natural slides could grow large and run fast. Loose avalanches may even serve as the trigger for lingering slabs as they descend. Remember the slopes above your head may bask in the sun even as you travel in the shade.

    (1/23/2021) Example: Natural loose wet avalanches on steep sunny slopes. Similar conditions are expected on Tuesday. Photo: Susie Glass

  • Storm Slabs

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

    Natural and human-triggered slabswere reported on Monday. While these slides remained small, given the amount of recent snow, several potential layers will continue to exist in the upper snowpack and could produce avalanches. You are most likely to trigger a lingering slab on a convex rollover, in rocky terrain, or near wind-affected snow. You can use small slopes and hand pits to test and track the changes in the storm snow. Pay particular attention to which direction a slope faces. Both sunshine and the recent winds may cause certain aspects to respond differently or change during the day.

    (3/21/2021) Uptrack tests like this can be performed by any mode of travel. They can highlight weaknesses within the new storm snow as you travel.

Avalanche Discussion

The recent warmer storm brought 6-12” of snow to most locations in the West South, with the greatest accumulations near the volcanoes. This adds to storm totals since 3/18. Paradise: 24-30”, Crystal 12”, White Pass 12-14”, Chinook Pass 18-20”. All this recent snow sits above a crust (3/18). On southerly aspects, a very thick and firm crust exists. In shadier areas, the crust may appear very thin, weak, and even unnoticeable. Any avalanche issues should remain above this 3/18 interface. 

During the recent storms, large thin cornices formed. Several natural and triggered cornice falls occurred on Saturday. As the sun comes out and temperatures warm, you could see more of these waves of snow collapse. Choose routes that limit the amount of time you spend below these looming beasts. 

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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