Avalanche forecast

Mt Hood

Northwest Avalanche Center
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Avalanche danger

Thu
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Wind slabs will build throught the day on exposed lee slopes and they could be large at upper elevations. Although the new snow should fall "right-side-up", winds redistributing that snow will create punchy drifts that you could trigger above the refreezing crust. Steer around steep windloaded start zones and mid-slope rollovers.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2

    Following Tuesday's rainfall, we expect new snow totals through Wednesday will be in the 4-6" range at middle elevations and more like 6-10" at upper elevations. Although much of this snow falls overnight with moderate WSW winds, those winds will keep redistributing the snow even as snow showers become lighter on Wednesday. Slabs will be larger, more reactive, and more difficult to steer around at upper elevations, becoming easier to isolate and steer around as you head into middle elevations. Note areas of active transport, fresh, sharp corncies, and the lee slopes that are actively accumulting snow. These are the features worth steering around. But given the duration of "prime wind slab speeds", we think that slabs are also likely to form on mid-slope rollovers. Note the average depth and quality of bond of the new snow above the crust. Also note the depth of slabs on small lee test slopes. Give these test slopes a stomp to check for cracking and propagation. Expect these slab depths to grow in size and cohesion as you ascend higher in the terrain. Manage the slab size and associated consequences by dialing back your terrain selection, reducing your slope angle, and seeking wind sheltered and less consequential features.

    Example: Signs of fresh wind loading.

    Photo: Joe Dellaporta

Avalanche Discussion

Around 0.6" of rain fell on existing crusts up to an estimated 8500 ft or so on Tuesday. By late in the day, snow levels dropped below 6500 ft while precipitation rates remained elevated with 25-30 mph WSW winds redistributing the snow as it falls at upper elevations. These higher snowfall rates should linger into the early evening hours, followed by lighter snow showers that will continue through Wednesday. Note that significantly more snow may have fallen on the upper elevations of Mt Hood, so prepare to make your own assessment if you head to these elevations. However, during periods of strong active wind loading, isolated natural avalanches would not be surprising, originating mostly above NWAC forecast elevations and  potentially descending into upper elevation band.

By contrast, if the winds die down, and the sun makes an appearance, reduce your exposure to steep snow-covered slopes, particularly those above you as rollerballs and snow shedding off rocks or cliffs may give rise to small wet loose avalanches.

Recent observations illustrate significant loss of snow coverage on windward aspects, along ridgelines, and at lower elevations following multiple days of warm temperatures. Fresh snowfall may thinly mask riocks and other obstacles. Snow bridges have become tenuous or fully melt out in recent days. Ride with caution if you're in one of these shallower snowpack areas.

Observations from the north side of the mountain have been limited, but conditions look rugged from afar with pockets of old drifted snow, scoured ice, and rain runnels from last week. NWAC forecasters spotted numerous large crowns that likely failed during last week's natural cycle. You will likely continue to find debris piles and old crowns from that impressively stormy week as you move around the mountain in the coming days. Check out the photos in the gallery for snapshot.

Are you heading out? Let us know what you see by submitting a public observation here or on the AvyApp. 

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