• 1980 Eruption
  • 2004 - 2008 Eruption
  • Crater Glacier
  • Past Eruptions
  • Facts and Research
  • Eruption Impacts and Return of Life
  • Changing Landscape
  • Facts and Research
  • Guided Hikes and Programs
  • Youth Volcano Camps
  • Field Trips
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  • Overview
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  • Geology Lessons
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  • Plan Your Field Trip
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  • Useful Links

    • Lahars: Introduction

    Lahars (volcanic mudflows) scrubbed river valleys of vegetation and deposited new layers of sand and boulders. Decades after the eruption, shifting channels and periodic flooding continue to influence vegetation recovery.

    Back to Return to Life
    USFS / Fred Swanson USFS USFS / Fred Swanson University of Washington / Jerry Franklin USGS / Lynn Topinka USGS / Lyn Topinka USFS / Jim Hughes USFS USFS / Peter Frenzen University of Washington / Charlie Halpern USFS / Tom Lisle USFS / Peter Frenzen USFS / Peter Frenzen USFS USFS / Peter Frenzen USFS / F. Valenzuela USFS / F. Valenzuela USFS / Peter Frenzen USFS / Peter Frenzen
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    The Mount St. Helens Science and Learning Center is a collaborative effort of the Mount St. Helens Institute and the U.S. Forest Service, Mount St. Helens National Volcanic Monument. Our mission is to connect people with nature through science, the arts and adventure recreation.

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