Lawinenlagebericht

Stevens Pass

Northwest Avalanche Center
Auf der Karte ansehen

Lawinengefahr

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

Kernpunkte

You can trigger avalanches at all elevations and large avalanches are possible in wind-drifted areas at mid and upper elevations. East winds will drift snow and form fresh slabs on Thursday. Prepare for very cold temperatures and deep snow hazards.

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Likely
    Größe
    1–2

    Use extra caution on all slopes steeper than 35 degrees. If you see cracks shooting through the snow, stick to lower-angle terrain. Use small test slopes to see if the snow slides easily. You can avoid triggering these avalanches by sticking to lower elevation, wind-sheltered terrain, or scoured, windward slopes. 

    Watch for plumes of blowing snow as an indicator of where fresh slabs are forming. Expect east winds strong enough to transport snow. Earlier in the week, older slabs formed with southwest winds. The most dangerous areas will be near and above treeline on leeward slopes below ridges exposed to east winds.

    You may still be able to trigger avalanches below treeline, avalanches won't be as big (but still dangerous) and they'll come in a wider variety of flavors. Expect wind slabs in open, wind-exposed terrain. In sheltered areas, you may still be able to trigger storm slab avalanches on recently buried interfaces in the top 2 feet of the snowpack.

Avalanche Discussion

On Wednesday, an observer in the Henry creek area reported cracks shooting long distances through the snow and audible collapses. This occurred on a layer buried over the weekend (Dec 18th) which has been slow to bond due to very cold temperatures. On Tuesday, observers reported easily triggering many soft slab avalanches in the upper portion of the new snow where a slightly heavier layer rested on very cold, dry snow. One observer was knocked over, partially buried by a slide, but uninjured.

Temperatures are extremely cold. Bring plenty of warm layers and monitor exposed skin for cold injuries. With all the new snow, falling in tree-wells and holes around creeks and boulders can be dangerous. Keep your partners in sight and within earshot.

Through Tuesday night, Stevens Pass picked up over 1.3" of water equivalent in the form of light, dry snow. This fell on another foot of very light snow that accumulated on Monday.

The December 18th interface holds weak grains of small facets, surface hoar, and crusts on southerly aspects. I found easy, sudden shears in snowpack tests on this interface on Monday. You may also find the December 8th surface hoar layer another foot lower in the snowpack. Weak layers, buried in late November, can be found near the bottom of the snowpack 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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