May 18th: On This Day in 1980 - Mount St. Helens

May 18, 1980: Mount St. Helens, a volcano located in the Cascade Range in the state of Washington, erupted at 8:32:17 am, causing the entire weakened north face to slide away, suddenly exposing the partly molten, gas-and-steam-rich rock in the volcano to lower pressure. The rock responded by exploding a very hot mix of lava and pulverized older rock toward Spirit Lake so quickly that it avoided the avalanching north face. The explosion caused over a billion U.S. dollars in damage and resulted in 57 human deaths.