Lawinenlagebericht

Olympics

Northwest Avalanche Center
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Lawinengefahr

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

Kernpunkte

Early season conditions, a recent storm, and a buried weak layer in the snowpack all lead to a high level of uncertainty in the Olympics. Even though it might not seem dangerous, ease into the terrain by using smaller, low-consequence slopes to gather information. Be particularly suspicious of areas where smooth pillow-like drifts formed on the lee side of ridges.

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–1.5

    While these may not be the classic very firm wind slabs frequently seen around the Olympics, scoured ridges and sharp cornices all hint at recently wind-transported snow. Don’t let the soft surface fool you. You may trigger fresh wind slabs on steep slopes below cornices, along the base of cliffs, or near exposed features. While these slabs should remain relatively small, with such a shallow snowpack, there are plenty of obstacles to hit if you take an unexpected ride in an avalanche. 

    What could make these particular wind slabs tricky is the presence of buried surface hoar in some locations. If you find a wind-loaded pocket over this extremely weak grain, it could trigger very easily. That may include remote triggers or causing the slide from lower on the slope. All the more reason to put plenty of distance between you and any wind-loaded feature.

    (12/8/2022)

    Small cornices and wind loading along a ridge. NE aspects were frequently loaded in this terrain. 

    Photo: Sam Luthy Siemens

Avalanche Discussion

A variable early-season snowpack, a recent storm, and a buried weak layer have us scratching our heads a bit more than normal. While the 4-6 inches of new snow may look soft and inviting, Friday won’t be the day to charge into the mountains. On Thursday NPS rangers and NWAC’s professional observer found surface hoar buried in the upper snowpack on a variety of aspects. This extremely weak persistent grain failed easily in snowpack tests. However, no avalanches were observed and small slopes did not produce any results. So, what does that mean? At the very least a weak snowpack structure exists near treeline. As more snow accumulates or the upper snowpack settles, it could form a slab and become more dangerous. Additionally, it can be nearly impossible to tell which slopes hold buried surface hoar and which do not. This poses a conundrum for backcountry travelers. Our best advice is to start small, use low-consequence terrain to gather information, and unless the slope is scoured to the ground or ice, be suspicious of the underlying snowpack. 

You can shape your communities avalanche forecast by submitting observations from your travels and help us fill in the gaps about this possible buried weak layer. 

Despite the fact it may feel like mid-winter, the snowpack is still shallow and plenty of obstacles exist to ruin your season. Watch for open creeks, holes near rocks, and shallowly buried brush.

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