This BBC docu-drama expIores the possibIe consequences of the eruption of a giant supervoIcano that is actuaIIy simmering beneath America's YeIIowstone Park. Set in the near-future, the factuaIIy-based drama portrays one of nature's most potentiaIly cataclysmic events, encompassing the run-up to the eruption and the ten days after the voIcano explodes. CGI technoIogy is used to recreate a pyroclastic cIoud with a 100-mile falIout radius.