Lawinenlagebericht

Central Cascades

Central Oregon Avalanche Center
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Lawinengefahr

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

Kernpunkte

We are in the midst of a major storm cycle with an abundance of new snow. During this time, triggering avalanches in new storm snow and wind drifted snow will be likely and natural avalanches will be possible. Avalanches can happen on all aspects and elevations; use your terrain choice to minimize your exposure to avalanche danger by sticking to low angle slopes less than 30 degrees. 

Lawinenprobleme

  • Wind Slabs

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

    New snow and wind is the recipe for wind slab avalanches and we have all the ingredients. We have an abundance of new snow coming in combined with moderate winds out of the west and southwest and wind slabs will build overnight and on Friday.

    Lee features below ridges and highpoints will be places where triggering wind slab avalanches will be more likely. Wind speeds will be sufficient to crossload slopes as blowing snow wraps cross slope around features. Be cautious with your terrain choice and remember wind slabs are most sensitive to triggering when they are fresh. 

    Avoid the big pillows of wind drifted snow in start zones.  Any time you see cracking in recent wind deposited snow or recent avalanches, recognize these as signs of unstable snow. 

    Use carefull evaluation in areas of sparse trees, clearings, and sections of dead forests. Open areas 'below treeline' can get enough blowing snow to create wind slabs.

    Archive Photo: Jim W

    Example of a small wind slab avalanche. Note the surface texture of the wind effected snow above the crown fracture. Ripply or pillowy surfaces are good indicators of wind loading. 

  • Storm Slabs

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

    On thursday the storm snow structure was 'upside down' with heavier snow over lighter weaker snow. With more snow coming in overnight and into Friday we may have multiple mid storm instabilities in the stack of recent snow. Storm slab avalanches can happen anywhere the wind has not stripped the snow away.

    Steep, convex, and unsupported terrain are the likely features for triggering storm slabs. Be especially cautious with your terrain choice to avoid being above terrain traps like constricted gullys, trees, and cliffs that could compound the consequence of being caught in an avalanche.

     

    Archive Photo: Aaron Hartz

    Small storm slab avalanche initiating on a convex roll.

Avalanche Discussion

Watch for cornices building at ridgetops. As the wind continues to move snow over ridgetops, cornices will grow over lee slopes and they will be fragile. They can be difficult to see, espeically in low visibility situations. Avoid stepping onto a cornice and breaking through to the slope below. 

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