Lawinenlagebericht

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Sawtooth Avalanche Center
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Lawinengefahr

Thu
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
1 · Gering
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Kernpunkte

Triggering a wet snow avalanche remains possible on sunny slopes, especially later in the day when the snow surface becomes moist. Avoid traveling in areas where you sink into a mushy, wet snowpack to keep out of harm's way.

Lawinenprobleme

  • Loose Wet

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

    Two varieties of wet snow avalanches are possible on steep, wind-sheltered slopes once surface crusts turn mushy:

    1. Wet Loose:  These avalanches are most likely during the heat of the day on slopes that face the sun. They often initiate near the bases of trees, rocks, and cliffs. Although slow-moving, these avalanches are surprisingly powerful and difficult to escape. They may also trigger larger wet slab avalanches (example) as they move downhill.
    2. Wet Slab: These large avalanches are unpredictable. They release as buried weak layers become wet. We anticipate these avalanches to break 1-4 feet thick, creating a dangerous, likely unsurvivable avalanche. They can break widely and without warning. The only way to reduce your risk is to avoid traveling on or under steep slopes. 

    Additional Discussion - Cornices: Avoid large, overhanging cornices. The heat will cause these to sag and break. Scary in their own right, they also serve as excellent triggers for the two wet avalanche concerns described above. 

    Large Wet Loose avalanche in the Northern Sawtooths near Williams Peak. NE 9000'.

    Photo: Sawtooth Avalanche Center

Avalanche Discussion

Last night’s above-freezing temperatures and partly cloudy skies likely led to a poor surface refreeze. Crusts will be thin this morning and short-lived as temperatures rise. If you’re entering steeper terrain, be mindful of terrain traps as the snow surface softens. While most natural wet-loose avalanche activity has already occurred, it’s still possible to trigger a slide that could knock you off your feet and carry you into hazardous terrain.

In previous days, cooler temperatures slowed the meltwater production at the surface of the snowpack, but they haven't stopped the movement of water within the snowpack. Wet slabs are unpredictable and can occur days after a warm-up, leaving us with some unknowns. We haven't seen widespread evidence of wet slab avalanches, but that doesn't mean we are out of the woods yet, and natural or human-triggered avalanches aren't totally out of the question.

To reduce your risk of triggering a large wet snow avalanche, plan to start and end your day early before the upper snowpack becomes wet and unsupportable.

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