Bollettino valanghe

West Slopes North

Northwest Avalanche Center
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Pericolo valanghe

Thu
Alta quota
2 · Moderato
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole
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In sintesi

Upper elevation wind slabs are where you're most likely to trigger an avalanche if you're going to trigger one on Wednesday. Slabs will probably be small in size, but consider steering around high-consequence steep slopes if they have wind drifted snow on them. 

Problemi valanghivi

  • Wind Slabs

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

    Wind slabs at upper elevations are where you're most likely to trigger an avalanche on Wednesday. More recently formed slabs will be the most reactive, and they will probably be small in size. Search for clues of wind loading, indicated by rippled, textured surfaces or smooth, rounded pillows. Drifts tend to  form on leeward sides of features. These include convex rollovers, gully walls, or around rock outcroppings and cliffs. 

    Approach steep, wind-affected slopes with caution, especially if they are in high consequence locations like around terrain traps. As most weaknesses are about a foot or less in depth, you can do simple hand tests or skin track cuts in order to determine if a slab may be reactive from a nearby lower-angle area. Increasing winds in the afternoon could help slabs grow in size. If in doubt, steer around steep, wind-loaded locations. 

     

    Small wind slabs built up on spots like this convex rollovers are where you're most likely to trigger an avalanche on Wednesday.

    Photo: Adam U

Avalanche Discussion

On Saturday, several small and large human-triggered storm and wind slab avalanches were reported. Since then a few reports of small human-triggered wind slabs have trickled in. Most avalanches failed on weaknesses within the new snow layer, above the Christmas crust and around a foot deep. More recent avalanches were mainly shallower, recently drifted snow. Temperatures are slowly warming and we expect the older slabs to continue gaining strength. Likelihood of triggering a larger avalanche is unlikely, but keep it in the back of your mind. Smaller recently formed wind slabs are where your most likely to still find reactive slabs. 

Snow fell Dec 30 to Jan 1, coating the Christmas crust with around 2 feet of snow. This is highly variable depending on your elevation and where in the zone you are. Since Saturday, moderate winds redistributed low density snow into variable surfaces and slabs in most near and above treeline areas.  Clear skies on Sunday initiated a few south-facing wet loose avalanches and a surface crust now sits on steep, south-facing aspects. Slightly warmer temperatures are also contributing to heavier snow, especially in below treeline areas. 

 

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