Bollettino valanghe

Mt Hood

Northwest Avalanche Center
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Pericolo valanghe

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Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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In sintesi

Additional light accumulations may keep wind-drifted slabs sensitive to your weight, especially if they sit over shallowly buried weak layers from the recent high pressure. If you find over 6 inches of recent snow, consider any steep, open slope as suspect. Give wind-loaded terrain some extra buffer and look for buried weak layers before riding or climbing on steeper slopes. 

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    Slabs of wind-blown snow have formed in exposed middle and upper elevation terrain. Another 1-3 inches of new snow and moderate SW winds may keep wind slabs reactive to a human's weight, especially if they break buried weak layers above the 2/7 crust. Most of these slabs will likely be on the smaller side, but I wouldn’t rule out the potential for a large avalanche in heavily drifted terrain. 

    These wind-loaded areas will be most prevalent on the leeward sides of ridges and moraines, below cornices, and beneath rock and cliff bands. Triggering avalanches in more sheltered areas is less likely, but not out of the question if over 6 inches of recent snow over capping surface hoar or sugary, near-surface facets.  

    Winds are forecast to decrease through the day, so use surface clues like ripples, dunes, and sharp drifts to help you identify nearby wind-loaded terrain. Shooting cracks or whumphs are obvious clues that you found an unstable slab. You can easily reduce your exposure to this problem by sticking to ridges or more sheltered terrain under 30 degrees. 

    Additional Discussion: There is some uncertainty regarding cloud cover. If the sun decides to poke out, be mindful of wet loose instabilities on steep sun-exposed terrain. 

    (3/31/2025)

    Ripples and cornices like this will help you pinpoint where wind slabs may exist. 

    Photo: Joe Dellaporta

Avalanche Discussion

Mt. Hood picked up about 4 inches of new snow by Saturday morning. The Mt. Hood Meadows Pro Patrol reported triggering small (D1) avalanches within wind-drifted snow at upper elevations. Most of these slabs failed about 4-6 inches deep at the new/old snow interface within previously skied terrain. 

The big question and uncertainty moving forward remains the distribution of recently buried weak layers, specifically surface hoar and near-surface facets above the 2/7 crust. While we likely don’t have enough new snow for these weak layers to be a problem yet, additional overnight accumulations on Saturday evening could start tipping the scales, especially in more wind-loaded terrain if this persistent structure exists. To manage this uncertainty, the best practice is to dig around and increase your margins around steep terrain. Shovel tilt tests or other snowpack tests would be effective tools to locate these problem layers. 

The 2/7 crust is a prominent marker in the upper snowpack. Right now, you’ll likely find this firm crust 6-12 inches below the snow surface. The snowpack beneath this crust is strong, so we’re mostly concerned about future avalanches failing on or just above the 2/7. Last week, we observed two widely propagating avalanches fail during avalanche mitigation work after we received 8-10 inches of new snow on February 9th. One of these is suspected to have failed on the 2/7 crust. 

We could use the observations as winter finally makes a return. Let us know what you see by submitting an observation here or on the AvyApp. 

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