Avalanche forecast

Mt Hood

Northwest Avalanche Center
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Avalanche danger

Wed
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

Avoid large runout zones and slopes steeper than 35 degrees as water continues to destabilize the upper snowpack. Wet avalanches typically fail without warning and the danger lingers long after water enters the snowpack. As temperatures cool, fresh snow and strong winds will build wind drifts that you can trigger on steep lee slopes above treeline. 

Avalanche problems

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    2–2.5

    Although temperatures cool slightly Monday night, we still expect over 1" of water added to the snowpack below 6500 ft by the end of the day Tuesday adding to significant water that entered the snowpack on Monday. Rain entering the snowpack prior to the cooling will still percolate through the snowpack above treeline. Natural or human-triggered wet avalanches are most likely during or shortly after periods of intense rainfall. Avalanches will gauge down to the 2/19 crust, entraining 6-18" of heavy, wet snow.  Boot penetration of 6" or deeper and rollerballs both confirm the problem in your terrain. Avoid slopes steeper than 35 degrees and don't linger under large avalanche paths.

    (4/3/2011)

    Example: Very large wet avalanche. A good reminder to avoid steep slopes above you on Tuesday.

    Photo: Robert Hahn

  • Wind Slabs

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

     Strong winds will build slabs quickly over a refreezing crust above treeline. Conditions may change rapidly at upper elevations as winds load new snow quickly onto lee slopes. You can use actively blowing and drifting snow or quick hand pit tests to identify and avoid steep wind-loaded slopes nearby. When in doubt, travel safely along ridgelines and through wind-scoured terrain which may have a refreezing crust at high elevation.

    Above NWAC forecast terrain, the snowpack remains dry and very large wind slabs may release naturally, potentially entraining wet snow and could travel to valley bottoms. Avoid lingering under steep slopes, particularly those connected to the upper mountain.

    (12/14/2021)

    Example: A small (D1) in Salmon River on a wind-loaded lee slope.

    Photo: Andrew Kiefer

Avalanche Discussion

Mt. Hood experienced picked up 1.5-2" of water equivalent as snow levels rose to 7500-8000 feet, peaking mid-day on Monday. The heavy rain comes on top of 3-4" of wet snow that fell Saturday night through Sunday evening. A widespread natural avalanche cycle may have occurred Sunday night, but we lack reports to confirm this. Prior to the storm, NWAC professionals observed 6-18" of snow above a strong (2/19) crust. This snow has settled 4" since water entered the snowpack.

As temperatures continue to cool, additional rain/snowfall may be heavy at times with continued strong SW winds. The wind slab hazard at upper elevations will increase while the wet loose avalanche hazard gradually decreases at these elevations. Choose safe and less exposed routes to ascend to elevations where you can recreate in dry snow. 

Creeks may have high volumes of water and few snow bridges. Cross these carefully or plan routes to avoid these potential obstacles. Some S and W aspects remain very shallow following an unusually dry late January and early February.

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