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
1 · Debole
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Non aggiornato — questo bollettino è scaduto 3 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Windslabs have been very touchy the past few days, surprising skiers and propogating across wide areas.   New snow accompanied by SW winds will increase this hazard.  Avoid steep, convex  and unsuported slopes.   In additon to the windslabs, we are at the tailend of a persistent weak layer down 2-3 feet.  We wouldn't want to wake this guy up with a windslab stepping down. 

Problemi valanghivi

  • Wind Slabs

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

    New snow and SW winds will increase windslab hazard on Wednesday.   I have been able to set off multiple windslabs everyday for the past 5 days!  A few of these large enough to bury a skier...or two.  N-E slopes at ridgetops will be the most loaded, but we could see loading reach down further into the terrain in open areas and potentially crossloading other aspects.  The current windslabs have been sliding on weak storm snow, but acting similar to persistant weak layers as they have been slow to heal and are propogating fast and wide.    My terrain choices have been very conservative as of late, avoiding the steeps, convex rolls and unsupported slopes.  Remember that burnt forests that are below treeline can present like higher elevation terrain without trees. 

    Photo: Jonas Tarlen

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely
    Dimensione
    1–3

    We still might have some isolated pockets of weak snow (facets) sitting just above a rain crust about 3' deep.  This layer was last active on Friday with multiple skier triggered slides.  These avalanches were accompanied by obvious whumpfing, collapsing and weak snowpack tests.   The whumps, collapses and snowpack tests have all been fading away.  Today I found no results in snowpack tests on that layer, and felt no collapsing, but I am not ready to pull this problem off the list.  It's most likely stubborn if anything.. but a windslab, (which will be easy to trigger on Wednesday!) could have the power to step down to this layer.  

  • Cornices

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

    Cornices have been slowly building with all the new snow over the past week.  They will continue to grow on North and East slopes with the new snow and SW winds.  They can break much further back than expected... give them space and respect.

Avalanche Discussion

This morning I didn't expect to bump the hazard from Moderate to Considerble.. but after seeing the ease at which the windslabs ran today, it seems appropriate.  It's far safer to use smart terrain choices than trying to outsmart the snowpack.  These windslabs have been a bit harder to get a handle on than usual.  Avoid skiing over trigger points and/or above terrain traps.  Use small test slopes and look for signs of cracking or collapsing.   Maybe hold off skiing complex or commiting terrain for a little longer. 

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