This BBC docu-drama explores the possible consequences of the eruption of a giant supervolcano that is actually simmering beneath America's Yellowstone Park. Set in the near-future, the factually-based drama portrays one of nature's most potentially cataclysmic events, encompassing the run-up to the eruption and the ten days after the volcano explodes. CGI technology is used to recreate a pyroclastic cloud with a 100-mile fallout radius.