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There are several active volcanoes in the state of Washington. On May 18, 1980, one of these volcanoes, Mount St. Helens, erupted. On March 1, 1980, the University of Washington set up a seismograph in the area to monitor the volcano’s activity. On March 20, a minor earthquake was recorded under Mount St. Helens and the entire area was put on alert. Thanks to this warning, the locals were able to evacuate before the mountain erupted. Before fully erupting, some steam and ash was seen billowing out of the top, and on May 18, the volcano was ready to blow. The mountain bulged and exploded out to the side. Super-heated gases and magma poured out to the side and in an instant, a supersonic cloud wiped out everything within 8 miles of the mountain. Afterward, a billowing 12 mile high cloud containing 540 million tons of ash drifted east across the United States.