Avalanche forecast

Mt Hood

Northwest Avalanche Center
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Avalanche danger

Fri
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
No rating
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Highlights

Reactive wind slabs from Wednesday will increase in size and distribution on Thursday as more snow arrives with stronger winds. Avoid all steep wind-loaded slopes, particularly if you find a firmer slab above lower-density snow atop the crust. Don't forget about shallowly submerged obstacles until we're further into this storm cycle.

Avalanche problems

  • Wind Slabs

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

    Cooling temperatures, increasing winds, and 3-5" of snowfall in the next 24 hours will build upon the touchy slabs observed on Wednesday. Observers in the Timberline area found slabs failing within a subtle layer of less wind-affected snow with the potential for slabs to fail down to the crust. We think that the additional snow and wind loading will stress existing weaknesses in these surface snow layers faster than they can heal, while also forming new layers of concern. Although slabs may not be as "touchy" as on Wednesday, once triggered they could be large and break more widely across a slope. Expect to find rapidly decreasing stability as you climb from 5500-6500 ft with dangerous conditions and widespread potential for human-triggered avalanches as dry snow depths increase and new/recent wind transport intensifies.  While most wind loading and slab activity was focused on N and NE aspects on Wednesday, as winds shift gradually more westerly, expect slab activity to spread onto other aspects, particularly on the eastern side of ridgelines. Note cracking, as you move into wind-affected terrain. Use small test slopes to gauge the potential for propagation. And avoid heavily wind-loaded slopes, particularly opposite scoured ridgelines and beneath fresh, sharp cornices.

    At middle and lower elevations, this has been just enough snow to make the early-season submerged objects dangerous. Whether a small avalanche rakes you through the terrain or whether you hit these objects, it's not worth the risk to travel quickly at these elevations.

    (1/3/2024)

    Small intentionally triggered avalanche avalanche on a N or NE aspect around 6500 ft. These will be larger and could take you for a more consequential ride on Thursday.

    Photo: Ryan Matz

Avalanche Discussion

Mt Hood only picked up 1-2" of snow in the last 24 hours, but it's the sustained moderate winds that ramped up the risk of human-triggered avalanches on Wednesday. A snow pit from 6500 ft near Timberline shows a stiffer slab over Tuesday's less wind-affected snow, sitting on the crust. Cooler temperatures are helping to preserve the weaknesses within the upper snowpack and we think that similar conditions will be in play on Wednesday.  Keep in mind the uncertainty regarding new snow amounts at upper elevations given persistent clouds and fog that limited observations at these elevations over the last several days.

Mt Hood picked up around 0.3" of water along with short periods of intense snowfall during the mid-day hours. Clouds limited observations above the treeline. A few more inches of snow may arrive Tuesday night with light to moderate winds. Wednesday could feature clouds and snowfall in the morning, with a chance of sun breaks during the mid-day hours, then winds ramping up as clouds and perhaps snowfall returns late in the day. If the sun does come out, rollerballs are your cue to stay out from under steep slopes receiving direct sunshine where snow could shed off rocks and cliffs.

On Saturday, NWAC observers traveled to the Tilly Jane area in the rain shadow of Mt Hood. They observed little snow cover until 5500ft.  Snow became deeper above this elevation but remained wet and shallow until almost 7000ft.  Above 7000ft they found 1 inch of new snow on a stout melt-freeze crust.  

Backcountry winter recreation on snow is limited to middle and upper elevations at this point, but we hope that at some point during this storm cycle the lower elevations come back into play. While on the snow, watch for shallowly buried objects such as rocks, creeks, and thinly bridged or even open crevasses. These hazards can exacerbate the consequence of a long fall or small avalanche. 

Avalanche forecasting is a community effort. Let us know what you see by submitting a public observation!

NWAC may issue a gray "No Rating" for an elevation band when there is not enough snow to present an avalanche hazard.

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