for National Geographic News
When Mount St. Helens erupted 25 years ago, the north face of the volcano collapsed in a massive rock-debris avalanche. The landslide and the accompanying flow of searing gases instantly obliterated the surrounding landscape in southwestern Washington State on May 18, 1980.
(Recent eruptions have been markedly less cataclysmicsee recent photo.)
In 1980, after flying in by helicopter, Virginia Dale was among the first ecologists to see the devastation up front.
"It appeared to be totally lifeless," said Dale, who works at the Oak Ridge National Laboratory in Tennessee. "Everything was gray. There was nothing there."
Or so it seemed.
On closer inspection Dale found pockets of survival, often something as small as a piece of root close to the surface. When she came back in summer, she saw that a few herbs known as lupines had begun to spring to life. "The fact that anything could do that was just phenomenal," she said.
In fact, scientists are stunned at the area's recovery. In the 25 years since the eruption, Dale has counted more than 150 species of wildflowers, shrubs, and trees that have returned to the debris deposit she has been studying.
To Dale and other scientists, Mount St. Helens has been a unique natural laboratory in which to test models of ecological recovery after a natural disaster.
The ecological recovery turned out to be different than the models had predicted. "The patterns of impact and destruction were not as anticipated, and survival and establishment [of new plants and animals in affected areas] have also been different than theory would have predicted," Dale said.
Dale, who received National Geographic Society funding for her research, is the co-editor of a new book, Ecological Responses to the 1980 Eruptions of Mount St. Helens. The book documents the research of dozens of scientists studying Mount St. Helen's comeback. She is also the co-author of an article on the St. Helens that appears this week in the academic journal Science.
Breaking the Rules
Mount St. Helens erupted with 500 times the force of the Hiroshima atomic blast. The accompanying landslide was the largest in recorded history. Forests, meadows, streams, and lakes were turned into ash-gray wastelands.
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