Bollettino valanghe

Flathead Range & Glacier NP

Flathead Avalanche Center
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Pericolo valanghe

Fri
Alta quota
1 · Debole
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

It's the winter solstice, so of course the primary avalanche concern is... triggering wet snow avalanches on very steep slopes at mid-elevations. These may ruin your holidays if they carry you into a terrain trap, like a gully, dense brush, trees or rocks. Recent or triggered roller balls on steep slopes are a reliable indicator that these slides are possible. 

Problemi valanghivi

  • Loose Wet

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

    You can trigger sluffs of dense, wet snow on mid-elevation slopes steeper than about 38 degrees. These can be dangerous on slopes above terrain traps or slopes without low-angle benches that can slow moving debris. Rollerballs that fan out from your machine or boards are a reliable sign that the surface snow is wet. Step back to lower-angled terrain if you see these conditions. This hazard may be more widespread on shaded slopes where the surface snow is getting wet for the first time. 

    Below 6000 feet, we found a shallow, wet snowpack on sunny slopes. We were able to release rollerballs but did not trigger any wet loose slides.

    Photo: blase reardon

Avalanche Discussion

They said there'll be snow at ChristmasThey said there'll be peace on EarthBut instead it just kept on raining

                                - "I Believe in father Christmas," Emerson, Lake & Palmer

Another 48 hours of above-freezing temperatures and light rain across the region is testing my faith in Father Christmas. And Cold Miser, Jack Frost, Boreas, Skadi, and any other deity associated with snow. On the plus side, however, the warm snowpack is steadily degrading any buried weak layers. If - once - winter arrives, we'll be dealing with new snow avalanche concerns. And despite the soggy conditions, we found decent turns Wednesday east of WMR.

For the solstice - yes, the winter solstice, which is tonight at 7:27 - wet snow avalanches are the primary avalanche concern. This hazard is specific to very steep, mid-elevation slopes with more than a few inches of wet snow at the surface. It's isolated at upper elevations, where temperatures have mostly remained below freezing. And also isolated at low elevations, because, well, the snow cover is too thin to pose much danger on most slopes. 

The Persistent Slab avalanche hazard that dominated concerns for the first few weeks of the month remains a lingering concern above about 7000 feet. A layer of surface hoar and facets is buried 1 to 2 feet deep (12/1) and *might* be sensitive to a person's weight on the isolated slopes where it's not shielded by a sandwich of ice layers and refrozen wet snow. The forecast team has looked for that structure in the past few days but did not find many signs of instability in the northern Whitefish Range, east of Whitefish Mountain Resort, the northern Swan Range, or Tunnel Ridge in the Flathead Range. If I made it above the rain-snow line today and tomorrow, I'd still check for the 12/1 surface hoar and facets before committing to steep, consequential terrain. Particularly on northerly slopes, where the layer was more developed and the 12/7 crust may be thinner.

Maybe a little reverse psychology is in order. No more snow dances or ski sacrifices in bonfires. Maybe dancing to reggaeton, Bad Bunny, or Jimmy Buffet in hula skirts and flip flops.

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