Mount Tambora is a volcanic mountain in Indonesia. It may be hard to imagine how an eruption there could affect the Great Plains, especially from so far away on the other side of the world. But on this date in 1815, it did exactly that. The eruption began on April 5, with small tremors hinting at a major event. Then, on the evening of April 10, a cataclysmic explosion blew the mountain apart. A thick cloud of hot rock fragments and gases, known as a pyroclastic flow, rolled down the mountainside. The explosion and the tsunamis it triggered killed 10,000 people and destroyed 35,000 homes. And that was just the beginning.