NOVA S31E15 Hunt for the Supertwister

NOVA Season 31 Episode 15 Online – Scientists, meteorologists and storm chasers try to uncover the secrets of F5 tornadoes, the largest, most powerful and most dangerous on Earth. Included are looks at how funnels form and the devastating 2003 tornado in Moore, Oklahoma, plus "tornado tourists," who pay companies to take them to the ferocious phenomena to see them first-hand.