Near midnight of March 28, 1982, El Chichón — an obscure, little-studied volcano in Chiapas State, southern Mexico — violently erupted, terrifying local villagers and prompting a confused, poorly executed evacuation. For the next five days, the volcano remained intermittently but only weakly active, so many evacuees were allowed to return to their homes. Then, on April 3 and 4, two powerful and lethal eruptions occurred. Ground-hugging, high-speed torrents of hot gas and burning rock fragments swept down all sides of the volcano, obliterating everything in their paths. The eruptions killed about 2,000 people, mostly because of pyroclastic flows and surges that devastated nine villages around the volcano. Associated falling ash caused roofs to collapse, destroyed infrastructure and crops, and decreased visibility, necessitating road and airport closures. In addition to the fatalities, the eruptions caused severe socioeconomic hardships and disrupted the daily lives of many more thousands of people in the surrounding regions. Moreover, an unusually large amount of sulfur dioxide gas was injected into the atmosphere, which circled the planet over the next 20 days, affecting air traffic worldwide and slightly cooling the planet for more than two months after the eruption.