Lawinenlagebericht

West Slopes South

Northwest Avalanche Center
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Lawinengefahr

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

Kernpunkte

Continued snowfall and strong winds could start to build larger more dangerous avalanches, particularly at higher elevations. Look for clues like blowing snow, sharp cornices, and drifts to help anticipate wind-loaded slopes you want to avoid. Seek out lower-angled or less wind-affected snow to avoid this problem.

Lawinenprobleme

  • Wind Slabs

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

    Additional snowfall and windy conditions will help grow slabs on a variety of features Monday. With the winds shifting from W to E and back again, you may find wind-loaded slopes on any aspect, along cross-loaded features, and even in open areas below treeline. For the past several days these slabs have been smaller and easy to manage, however as they grow larger, they will be more dangerous to try and tip-toe around. You could even find harder wind slabs that can break above you. So, use visual clues like blowing snow, fresh cornices, and sharp drifts to anticipate wind-loaded slopes. If you see or feel firm pillow-like slabs steer around them and seek out lower-angled or less wind-affected snow.

Avalanche Discussion

This weather pattern continues to favor the volcanoes. Locations near Mt St Helens, Mt Adams, and Mt Rainier could see 8-12 inches of new snow along with strong and gusty winds. Closer to the crest Crystal Mt and White Pass may see less snowfall, but strong winds should still easily transport snow. So, while avalanches could be smaller near these locations, they may still trigger easily and release above you. 

Small human-triggered wind slabs were reported both Saturday and Sunday in the Tatoosh Range near Mt Rainier and in the Crystal backcountry. Observations also included blowing snow, textured snow surfaces, and slightly firmer shallow surface slabs. 

At lower elevations, wet heavy snow and rain have resulted in new rollerballs. This pattern should continue Monday, but we don’t expect any significant loose wet hazard from this storm. 

While we anticipate avalanche activity to remain within the new snow, if you stop and dig, take time to look at the entire upper snowpack above the Christmas Crust. In most locations, you’ll find 15-24 inches (40-60cm) of strong, right-side-up, well-settled snow over this very prominent snowpack marker. However, prior to the storm buried surface hoar (1/4 interface) was observed at White Pass by NWAC forecasters. Similar observations of buried surface hoar were made at Mt Hood Sunday. We aren’t entirely sure exactly where this layer could exist in the terrain, but it was most often found on NW-N-E aspects near treeline. Keep this on your mind if you’re traveling to these locations or Mt St Helens and Mt Adams where it could also exist.

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