Avalanche forecast

Mt Hood

Northwest Avalanche Center
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Avalanche danger

Sun
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

Active wind loading and light amounts of snowfall will maintain dangerous conditions at upper elevations. At middle elevations, slabs should be easier to manage by avoiding steep slopes with more than 6" above a crust. You can also still trigger a small wet avalanche until cooling strengthens the old snow.

Avalanche problems

  • Wind Slabs

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

    The wind slab problem becomes larger and more dangerous, with a much higher degree of uncertainty at upper elevations. The 1/3 crust extends to at least 6600 ft, but once you lose track of it, expect to find dangerous conditions with 1-2 ft of snow for avalanches to entrain. In areas where denser storm snow builds over recently buried weak snow,  you may trigger avalanches that break wider or from lower angle terrain than you'd expect. Stay off steep wind-loaded upper elevation slopes.

    At middle elevations, wind slabs should be smaller, moving around 3-5" of new snow expected Friday night through Saturday. Avalanche activity will be limited to terrain features where you see signs of active (blowing snow) or recent deposition (scour on the opposite side of the ridgeline, or fresh, sharp cornices). Steer around suspect lee slopes steeper than 35 degrees and be prepared for increasing reactivity as snowfall rates increase later in the day.

    Example: Shooting cracks in stiff pockets of wind drifted snow are a clear sign of instability.

    Photo: Joe Dellaporta

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    The wet loose problem is decreasing as cooler air starts to gradually refreeze the snow surface from the top down. However, at lower elevations, there might not be enough radiational cooling to form much of a crust over the wet snow. If you find 6" or so of heavy, wet snow that you can sink into, expect to trigger small avalanches on slopes approaching 40 degrees. These avalanches could get you into trouble above a terrain trap such as a creek or cliff band.

    (12/2/2024)

    Avoid complex terrain in areas where you find yourself sinking into wet snow or see evidence of wet snow avalanches. 

    Photo: Joe Dellaporta

Avalanche Discussion

As expected, the Thursday-Friday storm brought wild weather to Mt Hood with 1.5-2" of snow water equivalent by the end of the day on Friday. The storm started with 5" of snow on Thursday, but the rain/snow line rose to around 6200 ft Thursday night. Rain was reported to 6600 ft early Friday, making generally small wet avalanches easy to trigger by Mt Hood Meadows patrol. Temperatures cooled in the early afternoon, bringing snow back down to the ski areas bases, but only a dusting to an inch of snow has accumulated. The wet snow will start to refreeze from the top down Friday night and Saturday, forming a new interface at all but the highest NWAC forecast elevations. 

We don't know how high the 1/3 crust will extend in the terrain on the south side of Mt Hood. This crust may be thinner or non-existent in some terrain on the drier NE side of Mt Hood - we simply don't know.  Widespread surface hoar that formed earlier in the week up to 7000' may make avalanches more likely in some areas.  In the nearby East South zone, we have a confirmed slab above this buried surface hoar layer, justifying a persistent slab problem. Therefore, take heed of any unusual signs of instability, such as long shooting cracks, whumphs, or fresh natural or human triggered avalanches. Any of these signs should have you dialing it way back to slopes less than 30 degrees.  A video in the gallery illustrates the problem in the East South zone. If you don't find a supportable crust in your terrain, you'd be wise to carefully evaluate the snowpack before engaging with larger open slopes or unsupported features, where a more slab failure would put you in harm's way.

The overall snowpack coverage has improved rapidly over the last few weeks, especially compared to last year!  Let us know what you see by submitting a public observation. 

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