Top Historical Moments on Instagram: "On May 18, 1980, Mount St. Helens erupted in one of the most catastrophic volcanic disasters in U.S. history. It became the deadliest and most economically destructive eruption ever recorded in the contiguous United States. After more than a century of dormancy, the volcano showed alarming warning signs in early 1980. Earthquakes shook the region, and magma rising beneath the surface caused the mountain’s north flank to bulge dramatically. At 8:32 a.m., a ma