Bollettino valanghe

Central Cascades

Central Oregon Avalanche Center
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Pericolo valanghe

Thu
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato
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Non aggiornato — questo bollettino è scaduto 4 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Wind slab avalanches will be likely on North and East slopes at treeline and in Alpine elevations.  Heavy snowfall and Strong winds overnight will continue to load these slopes.  Be wary as Strong winds can create unusual loading patterns, meaning wind slabs may exist lower in the terrain than you might be used to.

Problemi valanghivi

  • Wind Slabs

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

    It shouldn't take a lot of sleuthing or subtle clues to see that it was very windy on Tuesday.  In the time I was out touring at Todd Ridge (maybe 2 hours) 4 or 5 new trees fell across the road!  The heavy snowfall and Strong winds that we saw today will continue overnight before gradually letting up Wednesday mid-day.  Wind Slabs will surely exist on North and East slopes up high.  Sometimes these lee start zones load and release several times during a storm.  Other times they harbor a very large, stubborn wind slab.  Additionally, Strong winds can redistribute the snow in unusual ways , sometimes removing it completely, and other times loading it further down slope.

    If you choose to travel on lee slopes Wednesday, careful evaluation will be important, and avoidance of steep unsupported terrain is always a great option.  Watch for where cornices have grown recently, and signs of wind consolidated snow like cracking or marked changes in ski penetration.

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–1.5

    On Tuesday I didn't see any evidence of Storm Slab avalanches.  The new snow was "adhering" well to the old saturated snow.  As temperatures continue to fall I'm inclined to discount the Storm Slab problem for Wednseday as well.  Nonetheless with well over a foot of new storm snow it would be foolish to rush into steep terrain or onto slopes with terrain traps before first evaluating the new snow.  Test slopes (small, harmless slopes that are 35-45 degrees) are my gold standard for doing so.

Avalanche Discussion

On Tuesday afternoon I was finding 15 cm. of new storm snow at Todd Ridge.  Strong winds (even below treeline) were redistributing the snow.  Immediately beneath our most recent snow the snowpack is saturated from the most recent rain.  How much snow is saturated varies widely based on elevation but also a bit locally, presumably due to pooling and runnels within the snowpack.  I could still identify the buried surface hoar layer at 50 cm. down.  This layer hasn't produced any avalanches for over two weeks.

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