Lawinenlagebericht

Stevens Pass

Northwest Avalanche Center
Auf der Karte ansehen

Lawinengefahr

Tue
Hochgebirge
3 · Erheblich
Waldgrenze
3 · Erheblich
Unterhalb
2 · Mässig
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Veraltet — dieser Lagebericht ist 4 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

Expect to find challenging travel conditions with a supportable, slick ice crust, breakable ice crust to mushy snow. Another shot of rain will continue to saturate the snowpack and increase chances of wet avalanches, both loose and slab. Steer around steep slopes if you observe avalanches that entrain wet snow.

Lawinenprobleme

  • Loose Wet

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Likely
    Größe
    2

    Heavy sleet and freezing rain fell on Saturday and Sunday. There may be a stark difference between the snowpack at and west of Stevens Pass vs further east in the zone. One thing is more clear-it will rain more Sunday night into Monday. Water should continue to percolate into the snowpack. As it undergoes a transition to wet snow, you may be able to trigger wet slides that entrain deeper snow and become large. Widely propagating wet slabs could also be possible as water filters down the previously dry snowpack. Recently buried layers of small facets and surface hoar could act as the weak layer for wet slab avalanches. In other areas you might just find challenging travel on a stout ice crust, or it could be breakable. 

    The current conditions are a bit unusual, and wet slides themselves can be hard to predict, so give yourself an extra margin of safety with your travels. Look for recent avalanche activity as the number one bullseye of instability information. Wet, mushy, and unsupportable snow are also good indicators that wet loose avalanches could be possible. 

    Example wet loose avalanche with some dirt in the debris.

    Photo: ONP Rangers

Avalanche Discussion

Highway 2 has been closed since the 24th due to thick freezing rain (see photo below). There may have been a round of wet slides on the 24th into the 25th, but information is limited. WSDOT did a round of control work on the 24th and reported a number of avalanches, one of which crossed Hwy 2. That storm was a complex battle between warm, wet air and very cold air. As a result, you could expect wet snow at mid and upper elevations, and a stout ice crust over dry snow nearer to the valley bottom. 

On the 18-20th, Stevens Pass picked up cold, dry snow with 3-day 24-hour totals reaching nearly 3 feet. The December 18th interface holds weak grains of small facets, surface hoar, and crusts on southerly aspects. Josh found easy, sudden shears in snowpack tests on this interface last week. You may also find a layer of surface hoar from December 8. Near the base, weaker snow buried in late November, can be found around a couple of crumbly crusts. While they haven't been involved in avalanches in over a month, a very big storm could activate them.

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