Imagine a mountain that had been quiet for over a century. Then one spring morning, the entire north side collapses. On May 18, 1980, Mount St. Helens in Washington state produced one of the most destructive volcanic eruptions in American history. Scientists had been watching the mountain closely. For two months, small earthquakes shook the ground. A visible bulge grew on the north face of the mountain. They warned people to stay away. But the eruption was far more powerful than anyone expected. A massive landslide tore away the mountainside. Then a sideways blast of superheated gas and rock traveled at 300 miles per hour. The blast flattened 230 square miles of forest. Trees that had stood for hundreds of years fell like matchsticks. A column of ash rose 80,000 feet into the atmosphere. Ash drifted east and fell on towns hundreds of miles away. Cars, rooftops, and roads were buried under inches of gray powder. Fifty-seven people died, including a scientist named David Johnston who had been monitoring the volcano from a ridge six miles away. His last radio message was: "Vancouver! Vancouver! This is it!" The eruption reduced the mountain's height by 1,300 feet and left a massive crater shaped like a horseshoe. Today Mount St. Helens is a living laboratory where scientists study how nature recovers from disaster.