On May 20,1980, two days after the catastrophic eruption of Mount St. Helens, U.S. Geological Survey (USGS) scientists landed in a helicopter near the volcano's base, a short distance from what should have been the south shore of Spirit Lake. The lake, just 8 kilometers north-northeast of the volcano, was the largest of dozens of sub-alpine lakes battered by the eruption. Unable to see much that resembled a lake, the scientists suspected that Spirit Lake had either boiled away or was buried by avalanche debris. Further investigation revealed that the lake had survived, but it looked more like land than water because thousands of logs, tons of volcanic ash and other rubble blanketed its surface.
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