1980 eruption of Mount St. Helens
On May 18, 1980, Mount St. Helens in Skamania County, Washington, United States, erupted. The eruption was preceded by a two-month series of earthquakes and steam-venting episodes. An eruption column rose 80,000 feet into the atmosphere and deposited ash in 11 U.S. states and two Canadian provinces. Thermal energy released during the eruption was equal to 26 megatons of TNT....