Avalanche forecast

Mt Hood

Northwest Avalanche Center
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Avalanche danger

Fri
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Dangerous wind slabs lurk and continue to build near and more significantly above treeline.  Identify and avoid wind-loaded slopes steeper than 35 degrees, where lense-shaped pillows or firm/textured snow can produce a large avalanche. Travel safely by choosing lower angle or wind-scoured  slopes and wind-sheltered areas.

Avalanche problems

  • Wind Slabs

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

    At least 36 hours of moderate winds continue to move around approximately 6-12" of recent which has formed large and sensitive slabs that will continue to be reactive to human trigger on slopes steeper than 35 degrees.  As you ascend, you may notice wind-affected snow in exposed areas below treeline, with small slabs near ridgelines that you should steer around near treeline. However, large slabs above treeline will be large, potentially breaking widely across terrain features. Look for signs of active wind transport such as blowing snow and cornice development to clue you into where slabs may have formed. Pay attention to the snow beneath your feat for signs of cracking of the snow surface or a firm/punchy character indicative of wind slabs.  If you identify any of these red flags, retreat to lower angle terrain (less than 35 degrees) and navigate away from features such as cornices and convex rolls.

Avalanche Discussion

Winds will continue on Wednesday, relenting slightly into the 10-20 mph range at 5000 ft, and the precipitation should end. The sun may make an extended appearance from mid-day onwards.

Our most recent storm brought 6-12" of new snow from Tuesday night through Wednesday night with around 1" of water that came in warm and bonded well to pre-existing crusts. The best riding conditions may be found in wind-sheltered terrain below treeline,  but several other isolated avalanche problems may exist here, so low danger there does not mean no danger.

  1. Isolated wet loose avalanches may release where direct (but weak) November sunshine softens recent unconsolidated snowfall. Look for signs of of roller ball activity or wet snow that you can sink in deeper than your ankle. If you encounter these conditions, adjust your aspect to find cold snow surfaces.
  2. Enough snow may have fallen in some locations to produce an isolated storm slab. We have not included storm slabs as an official problem because we expect generally good bonding of the recent snow to the interfaces below, but you should still monitor the bond between new and old snow or crusts. Steer around convex rolls and slopes steeper than 35 degrees if you see signs of instability such as recent avalanches or cracking of unconsolidated snow.

With 45-50" of snow depth at mid elevation, our snowpack is far above average for this time of year.  After our initial snowfall, a rain event and warm period built a supportable rain crust on November 16th. This has served to lock in the base of the snowpack and batter down vegetation creating surprisingly good travel conditions and snow coverage for November.  Snow that fell last week is generally well bonded to the 11/16 rain crust and no significant avalanche activity was observed in the recent snow.  Friday and Saturday (11/20-21) brought sunny, calm, and warm conditions. The snow surface stabilized as a crust formed on solar aspects and lower elevations. Higher elevation and shaded slopes largely escaped the melt cycle and good travel conditions were found on these slopes throughout the weekend. The recent wind slabs sit on top of these crusts and higher elevation old snow surfaces. 

Despite the great start to our winter snowpack, keep early season conditions in mind. Rocks, stumps, and vegetation may be barely covered and many creeks are open.

The Covid19 pandemic continues to be a major health and safety concern. Avoid unnecessary risks that could result in a rescue or stress medical resources. Follow local and state guidelines and wear a mask when appropriate. Maintain social distance and recreate responsibly and closer to home. 

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