Bollettino valanghe

Central Cascades

Central Oregon Avalanche Center
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Pericolo valanghe

Wed
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato
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In sintesi

On Tuesday, avalanches will be possible throughout the terrain.  At higher elevations they are more likely and could be large in areas of wind blown snow.  The most dangerous slopes will once again be those north and east facing slopes beneath ridgelines or other features that catch the snow.  At lower elevations, heavy wet snow and possibly rain will lead to unstable snow on steep, unsupported slopes.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–2.5

    As is often the case when we are getting new snowfall, Wind Slab avalanches will be our chief concern.  Snow levels aren't forecast to rise above treeline elevations and that means that this higher terrain will get the most new snow.  Light and Moderate winds with Strong gusts by Tuesday afternoon will redistribute new snow onto north and east slopes.  At alpine elevations wind slabs will be large.

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–2

    On Monday, even our highest trailheads were seeing some mixed precipitation.  Even where precipitation was falling as all snow, the snow was so wet that rollerballs and pinwheels were easily set in motion.  As the snow level rises above 7000 feet, Wet Loose avalanches will be likely on steep slopes as rain melts our latest snow.

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    On Monday we only got a few inches of new snow below treeline.  For the most part I saw instability take the form of big pinwheels rather than slab avalanches.

    On Tuesday, our Storm Slab problem will once again depend upon how much new snow we receive.  And once again, I think the deterministic forecasts are higher than is likely.  This heavier snow can be surprisingly forceful, and even relatively shallow slabs can be dangerous.  Small test slopes are my favorite tool for evaluating a storm slab problem.

Avalanche Discussion

Our cold, dry powder of last week is surely a thing of the past.  The current storm system can be characterized as warm and wet, and snow surfaces are what you would expect.  Observers have still been finding isolated pockets of buried surface hoar down about 50 cm., and some test slopes have revealed weak snow above the prominent rain crust from Feb. 8.  These observations have all been on north slopes near treeline.  I don't expect widespread avalanche activity on either layer, but they are worth keeping in mind, particularly with all of the moisture we are currently receiving.

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