Avalanche forecast

Mt Hood

Northwest Avalanche Center
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Avalanche danger

Thu
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
1 · Low
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Out of date — this forecast expired 6 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

You can trigger an avalanche at upper elevations where winds recently transported fresh snow. Steer around lee slopes steeper than 35 degrees and where you see active wind transport, firm or textured snow, or cracks forming in the snow as you travel. Travel safely by choosing lower angle slopes and wind-sheltered areas.

Avalanche problems

  • Wind Slabs

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

    After a fair-weather weekend, 2-3 inches of new snow fell Monday accompanied by strong and gusty winds. On Tuesday, Mt Hood Meadows Pro Patrol reported areas above treeline with wind transported snow in excess of 10 inches deep. As Tuesday night's storm impacts the mountain expect large wind slabs to develop rapidly on lee slopes above treeline and smaller wind slabs to develop near treeline. Look for signs of active wind transport such as blowing snow and cornice development to clue you into where slabs might be forming. Stay alert for firm and textured snow surfaces and cracking in the snow as you travel as evidence that you could trigger a wind slab.  Where you see evidence of wind transport choose lower angle terrain (less than 35 degrees) and navigate away from features such as cornices and convex rolls.

    Blowing snow, firm and textured snow, and cornice formation are all evidence that wind slabs are likely to be forming on lee slopes.

Avalanche Discussion

An early start to winter has brought us around 40" of snow at many trailheads. 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. Winds on Tuesday were able to redistribute the small amount of new snow from Monday and develop wind slabs at upper elevations on lee slopes. 

A storm arriving Tuesday night will bring significant snow and wind to the mountain. Expect to find wind slabs near and above treeline on lee slopes. Larger wind slabs will be more likely at higher elevations where wind has been persistent since Monday. New snow arriving Tuesday night and Wednesday will stack up below the treeline as well. The snowfall of the next 24 hours arrives with a cooling trend and falls on a stable snowpack, but the development of storm slabs may be possible in areas receiving more than six inches of snow in 24 hours. Watch for evidence of natural avalanches and cracks forming in the snow as you travel as a sign that you could trigger a storm slab. Evaluate the bond between new and old snow and steer around convex rolls and slopes steeper than 35 degrees.

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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