Lawinenlagebericht

West Slopes Central

Northwest Avalanche Center
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Lawinengefahr

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

Kernpunkte

Avoid travel in all avalanche terrain due to deep new snow, recent avalanche activity, and a variable snowpack. Expect very dangerous conditions to persist through the weekend with continued storms and warming temperatures.

Lawinenprobleme

  • Storm Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Very Likely
    Größe
    1–2.5

    Backcountry travelers triggered multiple avalanches up to 1’ deep in forecast zones adjacent to West Central on Friday. Look out for more and bigger avalanches triggered by heavy snowfall overnight and through the day on Saturday. Strengthening westerly winds will also amplify loading on leeward slopes. Natural avalanches are expected in terrain seeing continued snowfall and/or wind loading through the day. Keep an eye on what is overhead and avoid traveling down, across, or under any steep slope capable of producing an avalanche.

     

    (12/28/2020)  Example of a large slab avalanche with a 1'-2' deep crown.

    Photo: Colin Wiseman

Avalanche Discussion

Soft slab avalanches were easy to trigger in steep mid-elevation terrain on Friday, but observers in West North noted that hand pits and small test slopes showed little in the way of instability. They had to actually get into steep terrain to find out if they could trigger an avalanche. While wind transport was noted in some areas, avalanches and other signs of instability were found on slopes with few signs of wind loading. The White Chuck Tripod at 5000'  picked up about 15" of new snow in the last 24 hours. Convergence zone enhanced snowfall continued north of Hwy 2 while it decreased in other areas.

The biggest question mark is the extent of faceted snow at the 11/30 interface. In other zones it is quite widespread, making for a weak and concerning snowpack structure. Faceted snow was also found on the bed surface of some avalanches triggered today in West North. No matter how widely it's distributed, the old snow surface adds an extra layer of uncertainty and is cause for a more conservative plan if you want to avoid avalanches.

Lower elevations hold little to no snow, though an inch or two fell as low as Glacier on Hwy 542. Travel at mid-elevations is improving but the snowpack is still thin with plenty of hazards to ruin your day. New snow will barely hide some early-season hazards that were clearly visible in recent weeks.

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