Lawinenlagebericht

Mt Hood

Northwest Avalanche Center
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Lawinengefahr

Mon
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
1 · Gering
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Veraltet — dieser Lagebericht ist 4 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

New snow and wind will build fresh slabs that can be reactive anywhere you find 6" of snow above a refreezing crust. Steer around wind-loaded slopes steeper than 35 degrees, particularly if snowfall intensifies during the afternoon. We have limited information from above treeline and once the crust disappears, avalanches could become larger and more consequential.

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–1.5

    As snow levels lower, a fresh round of winds and snowfall will build slabs back into the near treeline, while slightly larger slabs build above treeline. Saturday's breakable crust up to 6600 ft only had a dusting to an inch of snow on top of it.  The crust should continue to strengthen and may become supportable by Sunday. You'll find the greatest hazard once the recent crust disappears. At these upper elevations, stronger winds will form slabs that may injure you. Near treeline, the depth of snow above the crust serves as a gauge for how much new snow has accumulated and how deep the drifts are in your terrain. Avalanches will most likely run on the crust. Once the drifts reach 6" or more, you can trigger an avalanche on a leeward slope 35 degrees or steeper. Small test slopes in wind-loaded terrain can give you a lot of information about the crust interface or old snow interface and the slab reactivity. We expect another day with limited visibility, so blowing snow and cracking beneath your mode of travel can also help you identify when conditions are becoming more hazardous.

    Below treeline, we expect limited hazard without sufficient drifted snow above the refreezing crust.

     

    Example: Shooting cracks like these coming from skis, snowshoes, feet, etc are indicators that a reactive wind slab exists.

Avalanche Discussion

Poor visibility continues to hinder our knowledge about recent avalanche activity, but below 6600 ft, Mt. Hood Meadows Pro Patrol reported limited hazard on Saturday.  About an inch of water on Wednesday night translated into 4-6" of snow between 5-6000' with moderate to strong SW winds before changing to rain Thursday morning.  Mild and windy conditions continued for the remainder of Thursday through mid-day Friday.  Temperatures were mild on Friday and slowly cooled on Saturday to form a refreezing, breakable crust which now has a dusting to an inch of snow on it by the end of the day Friday. Prior to Wednesday's storm,  NWAC forecasters found buried surface hoar sporadically throughout the landscape roughly 1.5' down in the snowpack (see photo). With the crust capping this layer in most locations, we don't expect the surface hoar to remain a significant concern even if it survived the rain event.

If you're out let us know what you see this weekend and submit an observation - any information is useful.

 

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