Mount St. Helens' eruption on May 18, 1980, was one of the most destructive volcanic eruptions in U.S. history. With an eruption column — the cloud of volcanic ash emitted during an explosive eruption — that measured 80,000 feet (24 kilometers) and that deposited ash in 11 states, the eruption caused damages estimated to cost $1.1 billion, according to the International Trade Commission. The eruption killed more than 57 people and destroyed more than 200 homes, according to the U.S. Geological Survey (USGS).
The new findings could help predict when the volcano will blow again and could be applied to other volcanoes, the researchers said, adding that their method will work on only some volcanoes. [The 11 Biggest Volcanic Eruptions in History]