Bollettino valanghe

Selkirk Mountains

Idaho Panhandle Avalanche Center
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Pericolo valanghe

Sat
Alta quota
1 · Debole
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole
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In sintesi

Calm weather over the past couple days has made for little change in snowpack stability since Tuesday’s avalanche forecast. At higher elevations, you can still find 20 cm of low-density snow over a firm crust. The snowpack is generally safe right now. The area of greatest concern can be found on open, steep (above 35 degrees), and wind loaded slopes (SE-E-NE-N) where you might be able to trigger a wind slab avalanche.

Problemi valanghivi

  • Wind Slabs

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

    Wind Slabs can be found on leeward sides of ridges. Mostly you'll find wind loaded aspects to be SE-E-NE-N, near high ridge lines. If the windloaded slope is steep (above 35 degrees) and is open (free of vegetation) then there are the ingredients needed to produce an avalanche. We haven't seen any signs of recent avalanche activity across the zone. These wind slab avalanches are unlikely but not impossible, and if you're going to trigger an avalanche, it'll be in an area like I just described.

    Matty Adams from Schweitzer Patrol assessing the low-angle skiing on Tressle Ridge in the Cabinet Mountains.  There's good traveling conditions on top of the supportable crust. 

Avalanche Discussion

Though the weather this past week has been sunny at high elevations (above 5000’), it’s been cold enough that there hasn’t been significant changes to the snowpack. Even the snow on south facing slopes is showing minimal signs of surface melt.

For the most part, the snowpack is around 200 cm deep across the zone. It’s made up mostly of strongly bonded snow that is likely to be a good base for the rest of the season. On top of the solid base of snow is the approximately 4 cm thick breakable crust, formed January 12th, that can still be found on all aspects and elevations. Finally, on the surface of the snowpack is a 20 cm deep, soft slab of snow that fell about a week ago. I’m surprised that the surface snow has been preserved as well as it has been. Minimal direct sun and wind, along with colder temperatures, have kept the ski and snowmobile conditions really nice!

There have been multiple rounds of Surface Hoar forming on the snow surface over the past week, which can be expected during clear weather. Surface Hoar formation is only a problem if it is buried by new snow, so…that’s the big question. We’re keeping a close eye on whether the Surface Hoar melts off or gets buried by the snow this weekend. 

Please submit an observation on the IPAC website if you’re out this weekend and notice changing conditions. I’ll be busy teaching a Level 1 Avalanche Safety Class, so it’ll be fun to keep tabs on what’s happening. Have a good weekend!

Regioni coperte