On May 18, 1980, the Mount St. Helens volcano in Washington State erupted. The eruption (which was heard hundreds of miles away) blew off the top of the mountain, destroyed miles of forest, and killed 57 people.
In the 30 years since the eruption, scientists have been able to study how an ecosystem recovers from a volcanic eruption. What was once a desolate, gray blast zone in 1980 is now home to many plants and animals. Although it has not had an eruption of the same size since 1980, Mount St. Helens is one of the most active volcanoes in the United States and could erupt again.
Read more about the potential danger from Mount St. Helens on National Geographic News.
See a gallery of images of Mount St. Helens on National Geographic.
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Photograph by Peter Lipman, USGS and Gene Iwatsubo, USGS