Bollettino valanghe

Olympics

Northwest Avalanche Center
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Pericolo valanghe

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

As the sun comes out Friday afternoon, you may see rollerballs and natural loose wet avalanches in the new snow. These slides should stay small and relatively harmless, but don’t let them push you over a cliff or into a creek.

Problemi valanghivi

  • Loose Wet

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

    With several inches of new snow and mid and upper elevations, if the sun comes out, it should easily cause the surface to become wet and unstable. Look for new rollerballs as your first indication that this process is occurring. Natural loose avalanches will likely follow. While most of these slides should stay relatively small, they can still hurt you if they push you into a terrain trap like over a cliff or into a creek. While we think it’s highly unlikely, if one of these small slides managed to entrain older wet snow, it could grow large. At this point, the problem has really changed from small and harmless to big and scary. If this is going to occur, it’s most likely on steep rocky slopes receiving direct sunshine. Don’t linger on our under these features unless you’re sure the snow is well frozen.

    (2/26/2022)

    Example: Large rollerballs initiating off rocks and cliffs as temperatures warmed late in the day.

    Photo: ONP Rangers

Avalanche Discussion

The Olympics may pick up a few more inches of snow Thursday night and Friday morning before the active weather pattern draws to a close. This will add to the 4-6” of recent snow from Wednesday night.  Below this surface, you’ll find the remnants of this past week's wet, wild, and often warm weather. Hurricane Ridge received more than 4” of precipitation during a potent atmospheric river that brought rain to near the tops of the highest peaks in the Olympics. Not surprisingly, this resulted in a widespread avalanche cycle on Feb 28 and March 1. NSP rangers on Thursday reported many large slab avalanches on NW-NE aspects. At least some of these slides failed on an older snow layer from mid-February. The most notable was in North Bowl where a very large (D2.5-3, R4) avalanche released. Other small slides were seen on other aspects and in rocky terrain.

Now that the main avalanche cycle has ended, we’re left with a very transformed upper snowpack. Below the new snow, a thin crust is trying to form as the recently wet snow freezes. In some areas, this crust may be supportable, in others breakable. The upper snowpack consists of alternating layers of crust, unconsolidated melt-forms, and pockets of dry snow. While individual snowpack tests may fail, given the nature of the recent precipitation event, it is unlikely that any of these layers are consistent across a slope. 

You may find a wide variety of snow surfaces. Bumpy rain runnels, breakable crusts, wet heavy snow, and icy slopes could all await you as you travel. Make sure to give yourself time and options to deal with these potentially difficult travel conditions.

Regioni coperte