Bollettino valanghe

Selkirk Mountains

Idaho Panhandle Avalanche Center
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Pericolo valanghe

Sat
Alta quota
3 · Marcato
Limite del bosco
2 · Moderato
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

Strong winds and new snow have created dangerous avalanche conditions at upper elevations. Easily triggered wind slabs can be found on all aspects, but especially on northeast-north-northwest slopes. Stick to safe travel routes, which include ridges, low angle slopes and sheltered terrain. Carefully assess new snow amounts and keep an eye out for hollow feeling snow, propagating cracks or active wind loading.

Problemi valanghivi

  • Wind Slabs

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

    Fresh snow and strong southwest winds have created new wind slabs, primarily at upper elevations. New wind slabs are building above old wind slabs that formed last week and might be hard to identify as the new snow blankets the mountains. These older wind slabs may be stubborn, but they likely exist on all aspects. Yesterday, we found a sandwich of soft wind slabs. In the top 12'' of the snowpack we found firm wind packed snow over soft snow which sat on another layer of firm snow. Extended column and compresson tests failed easily in the new wind slabs (CT 2  20cm down, ECTP 1 @ 30cm down). You can avoid this problem by avoiding steep and wind loaded slopes above treeline. The best riding can be found in timber where the snow is sheltered from the southwest winds. Yesterday, we found the snowmobiling was deep, below treeline.

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely
    Dimensione
    1.5–2.5

    Facets above the January 13th rain crust are still showing signs of weakness at upper elevations on aspects with a thinner snowpack. Last week were seeing propagation in this layer on south and west aspects near treeline and the Flathead Avalanche Center has seen natural avalanches occur recently on this same week layer. On north and easterly aspects this layer can be found, but is not showing much potential for failure.  In most locations, it is buried approximately 2-3 feet below the surface and will have enough volume to kill or injure a person if triggered. Triggering this layer is a low-likelihood, but high consequence scenario. Avoid large open slopes that have a thin snowpack to minimize your exposure to this problem. The other persistent weakness we are seeing in the snowpack consists of a graupel layer that is very prevalent in the East Cabinets but has yet to produce concerning results

Avalanche Discussion

We visited the Selkirks via the Pack River yesterday. Brian and I snowmobiled a freshly groomed Jeru Mountain road and continued up towards Jeru, through the trees. We left the sleds at 5000' and ski toured up the ridge to 5840'. Below treeline we found deep powdery conditions with a firm base about 2 ft down. The new snow in the trees was soft and not wind effected. Once we travelled near treeline the snow became wind effected and visibility was challenging. There was a strong SW wind, loading NE-N-NW slopes. Our original plan was to ski a west facing slope off the ridge, but after seeing conditions we altered our plan. The new snow was so deep that any slope steep enough for us to make turns on, was too steep to safely ski. Our skis were diving too deep to make good turns on 30 degree slopes. It isn't a problem we experience in the panhandle very often. We ended up bailing down the same ridge that we trudged up. There were a couple good turns, but needed to use the skin track to keep our speed up. The snowmobiling was 'all time' though! Over the windshield good! I'd recommend looking for good conditions in the 4000'-5000' range. Be aware of your surroundings and avoid runout zones and creek beds. Stick together and keep close track of folks in your party. It's deep out there!

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