Lawinenlagebericht

West Slopes North

Northwest Avalanche Center
Auf der Karte ansehen

Lawinengefahr

Tue
Hochgebirge
3 · Erheblich
Waldgrenze
2 · Mässig
Unterhalb
1 · Gering
Open full map
Veraltet — dieser Lagebericht ist 5 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

Backcountry users triggered avalanches in steep, wind-loaded terrain on Sunday. You'll still be able to trigger avalanches in thicker and stiffer wind-affected deposits Monday, so avoid higher-angle locations where you encounter stiffer wind-textured surfaces. When the sun is shining, stay alert for rollerballs or small wet loose avalanches which might run from steep, possibly rocky, areas on south-facing slopes. 

Lawinenprobleme

  • Wind Slabs

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

    Backcountry users triggered avalanches on wind-loaded mid and upper elevation steep slopes Sunday.  The terrain was mainly east-facing, but it could vary depending on local topography. Wind slab avalanches are the main problem to watch out for on Monday, especially at upper elevations where the wind shifted more snow around. Avalanches occurred on layer changes within the storm snow layers, a few inches above the old snow crust, up to about a foot and a half deep. Failures could occur deeper depending on how wind-loaded the slope is. Winds could be stronger than expected on Monday, possibly forming reactive wind slabs in locations that were not reactive previously. 

    Pay attention to snow surfaces as you travel, and search for active wind loading. Notice textured snow surfaces, and firmer-feeling snow. Cracking was noted as an obvious indicator for when people transitioned onto wind slabs on Sunday. Use these indicators to determine where to or where not to travel. Avoid steep slopes where you find wind-loaded snow. 

    Some backcountry travelers in the West North Zone noted traveling  up to 5000ft or more and not encountering wind-loaded slopes, finding generally uniform and right-side up snow.  In non-wind loaded areas, such as those, you may find dry loose avalanches easily running in the top few inches of snow- not enough to bury you, but they could knock you off your feet or surprise a person if they're below you. 

    (2/20/2022) A skier triggered slab avalanche on Huntoon Point in the Baker backcountry on Sunday. This was an obviously wind-loaded rocky outcropping. Approximately 18" deep, 150ft wid. N, 5100ft. Photo: Pete Durr, USFS Backcountry Ranger 

  • Persistent Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Unlikely
    Größe
    1.5–2.5

    Lingering concerns with the persistent weak layer exist now that another foot+ of snow loaded slopes. In upper elevation areas where this concern exists the new snow could be drifted into much thicker, heavier deposits.  An avalanche hasn’t been reported on this layer in over a week, but the new snow (weight) in the last 48hrs and a human trigger on top could tip the scales and we might see avalanches on this layer. It's buried 3 or more feet below the surface on upper elevation northerly aspects. Traveling onto upper elevation northerly slopes on steep terrain with the recent snow load might give you a small chance of being caught in an even larger avalanche. This is a low probability, high consequence scenario, and valuable to consider before heading out on these slopes Monday. 

Avalanche Discussion

Sun breaks are expected Monday, and small wet loose avalanches might occur on south-facing slopes. Pay attention to sky cover, and if the sun starts shining through, you may see rollerballs or small wet loose avalanches running in the new snow- especially from steep, rocky areas. Avoid traveling through these areas if you encounter snow naturally running on these steep, south-facing slopes. 

Abgedeckte Regionen