Bollettino valanghe

Mt Hood

Northwest Avalanche Center
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Pericolo valanghe

Fri
Alta quota
3 · Marcato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 4 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

You can trigger a large avalanche in wind-drifted snow at upper elevations.  The down-wind side of ridges, below cornices, and large slopes in the alpine are all likely spots you can trigger a large avalanche. Use ridgelines and more sheltered slopes to help you avoid these dangerous areas.  

Problemi valanghivi

  • Wind Slabs

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

    Northwest winds will be at work on Thursday drifting new snow into reactive wind slabs above treeline. These slabs will continue to grow in size as moderate to strong NW winds continue to blow new snow into slabs 1-2’ ft thick. If these slabs fail on the slick 1/14 bed surface, these avalanches may be quite large. These slabs will likely be most reactive during the morning hours just before winds start tapering into the afternoon. 

    You will find these wind slabs primarily on east-facing slopes, near and above treeline. Steep canyon walls, below cornices, and steep alpine slopes are all likely spots where you may encounter a large slab of wind-drifted snow. 

    With better visibility on Thursday, use visual clues to help you identify wind-loaded features. Look for wind-rippled snow, sharp cornices, and pillow-like slabs to help you identify slopes of concern.  Use more sheltered slopes and ridgelines to help you avoid this avalanche problem. 

    (12/30/2022)

    Use visual clues to help you identify wind-loaded slopes. In this case, sharp cornices are often are a great indicator of a wind-drifted slope beneath. 

    Photo: Joe Dellaporta

Avalanche Discussion

On Wednesday I went out to hunt for possible buried surface hoar from a cold and clear night on 1/16.  After digging holes in the snow in several different locations, I did not locate any buried surface hoar.  However, I did locate a couple layers that will be worth watching as we move forward. 

One layer being the 1/14 rain crust. In one location (5600, E aspect), I did receive propagating results with an ECT. Under further investigation, I did locate some small facets associated with this crust that likely formed after Mt Hood received one inch of new snow on the 14th followed by a fairly chilly night. This 1/14 crust now sits approxiamtly 12 inches below the snow surface. The second layer being the new/old snow interface, which sits within the upper few inches of the snowpack (as i write this). At this interface, it was easy to get planar results, specifically in areas that had a little more of a slab in wind-loaded areas. Check out my photo in the gallery for more info. 

After today my main takeaways is that we have a couple layers that avalanches could fail on in the future. One being (1/14 rain crust), that could produce a large avalanche, specifically in wind loaded terrain.  These layers will be worth tracking as snow piles up. 

Subtle changes in wind, precipiation, and sun can have a large impact on how the day plays out.  With some filtered sunshine, you may notice rollerballs and small wet loose slides on steep south-facing slopes below treeline. These will likely be isolated and small, however, keep an eye out and avoid these slopes if the warming becomes more intense than anticipated. 

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