Lawinenlagebericht

Mt Hood

Northwest Avalanche Center
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Lawinengefahr

Fri
Hochgebirge
3 · Erheblich
Waldgrenze
3 · Erheblich
Unterhalb
3 · Erheblich
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Kernpunkte

The ongoing thaw will maintain tricky and dangerous avalanche conditions. Expect the likelihood and size of wet avalanches to increase throughout the day, while concerns for avalanches in wind-drifted snow still linger. It's uncertain how the snowpack will respond to this jarring transition from winter back to spring; build in a wide margin for error and consider avoiding avalanche terrain altogether.

Lawinenprobleme

  • Loose Wet

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

    Expect 11,000-12,000ft freezing levels for the next 24 hours. With such warm temperatures, snow surfaces won't have a chance to freeze and gain strength Wednesday night. Wet snow conditions will exist right out of the gate Thursday, and the strong April sun will beat down on the snowpack and accelerate the thaw. The most dangerous conditions will develop on E-S-W aspects in direct sun, but you could encounter wet snow on any aspect and elevation by afternoon. Avalanches will run naturally and will be easy to trigger on slopes 35 degrees and steeper. These avalanches may start small and shallow but could grow large and gouge deeper as it continues to heat up. Wet loose slides in motion could even trigger slabs resulting in surprising avalanches. Choose simple terrain away from large avalanche paths as the snowpack takes time to adjust to these dynamic conditions.

    Example photo of loose wet avalanches similar to what we expect on Mt Hood over the next 24-48hr warm-up.

  • Wind Slabs

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

    Wind slabs that formed during the 4/3-5 storm are still settling and stabilizing. Slabs 2-4ft thick could still be reactive to triggers, especially in unsupported rocky terrain at upper elevations. There was a widespread natural avalanche cycle during the storm, and several wind slabs were triggered by Mt Hood Meadows Patrol over the past 2 days. These avalanches failed within new snow and on the new/old snow interface (Early April Crust). Some avalanches broke widely across terrain features and grew very large. Slab avalanche activity has decreased since the storm ended, and wind slabs appear to be gaining strength. But, the ongoing warm-up adds uncertainty, and cornices could also fall acting as huge triggers on slopes below. Pay attention as you transition into wind-affected terrain, and continue to avoid steep, unsupported slopes with evidence of fresh wind loading. 

    (4/5/2022) MHM Patrol triggered this large slab avalanche with explosives on Tuesday. (God's Wall, NE, 5400ft) Photo: Andrew Kiefer

Avalanche Discussion

It's rare to see such a cold winter storm immediately followed by such a dramatic warm-up. Wet loose activity was slow to develop Wednesday but the hazard should spike on Thursday. This may not be the average wet loose cycle you usually see on the first sunny days following a storm. These conditions are a very good recipe for avalanches due to:

  • The depth (2-3ft) and cold, low-density quality of new snow
  • Lack of an overnight freeze and 5000ft temperatures near 60F Thursday
  • Intensity and duration of the sun this time of year

We have a significant amount of uncertainty about how this day will play out. Don’t box yourself in by choosing routes that require you to travel through avalanche terrain to exit. As the warm temperatures increase our uncertainty grows and so does the potential for larger and more deadly avalanches. 

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