DAN CHAVAS (IMAGE) Purdue University Caption Dan Chavas is an expert at extreme weather: both the climate science that creates the conditions and the physics of the weather itself, including hurricanes, severe thunderstorms and tornadoes. Credit (Purdue University photo/Greta Bell) Usage Restrictions NONE License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.