Bollettino valanghe

Central Cascades

Central Oregon Avalanche Center
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Pericolo valanghe

Sun
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
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In sintesi

Triggering avalanches in recently wind drifted snow will be possible near treeline and above treeline on northerly, east and south facing slopes. Large and destructive avalanches failing on an old snow weak layer will be possible and primarily on west, north, and east facing slopes. Staying off recently formed wind drifts and  steep, convex, and rocky areas will help to minimize your exposure to avalanches. Anytime you are uncertain about the stability of the snow, you can travel on slopes less than 30 degrees and out from under steep slopes to avoid most avalanche danger.

Problemi valanghivi

  • Wind Slabs

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

    Wind slabs formed in the last two days will be trending toward less likely to trigger, but it is still possible. New shallow wind slabs will continue to build on lee features as snow trickles in overnight and on Saturday and as the  light winds out of the west move the cold light snow.

    Wind slab avalanches have the potential to "step down" into the persistent weak layer and create much larger avalanches on west, north, and east facing slopes near treeline. 

    Cracking in the wind deposited snow and recent avalanches are good indicators that you can trigger an avalanche. Wind slabs can be avoided by sticking to sheltered areas or slopes that have been scoured by the wind. 

     

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    2–2.5

    No recent avalanche activity has been reported on the January 31 weak layer. However, the structure is still there. On Friday, observers on north facing terrain below treeline found the layer of buried facets down around 3 feet below the surface. They reported no propagation in test results, but noted the layer is very weak.

     Triggering an avalanche associated with the current persistent slab problem will be more likely in isolated areas. Shallow rocky areas are trigger points that can bring the weak layer closer to the surface and thereby making an avalanche more easily triggered. Steep, convex, and unsupported terrain are also places where triggering an avalanche are more likely. At a basic level, managing a persistent slab problem is easy.....avoid avalanche terrain. Triggering an avalanche on this layer will be unpredictable and therein lies the tricky nature of a persistent slab problem. The "possible" rating should not be taken likely. Triggering an avalanche on the Jan. 31 facets will result in large avalanches. Non event feedback does not mean the problem is not there. In the last week, there have been no reports of  cracking, collapses, and whumping and we are now less likeley to get that feedback.

     It is worth digging into the snowpack to check for this weak snow on southwest and southeast facing slopes before riding in steep and consequential terrain.

Regioni coperte