Peggy Willenberg and Melanie Metz Trockman are the Twister Sisters, they are storm chasers. Armed with science and fueled by passion, they pursue tornadoes with a vengeance. Following these supercells and tornadoes the Twister Sisters log over 15,000 miles a year driving through the heartland of America. April through June is tornado season across most of the United States. This season was the slowest in over 50 years. In the months of April,May and June there were no tornado fatalities when annually the tornado seas on average's 55 deaths. The tornado is always an enigma,' Willenberg says, explaining the pull of the chase. ņAnd it's a puzzle I want to solve. It's symbolizes the great unknown to me. And I just have to keep on going and going and going because I can never get enough of that. I would never dream to assume I could ever conquer or control nature. But to understand it, that's almost as powerful."