Giant Hailstones Pummel Scientists

December 27, 2012—In the American Midwest's infamous Tornado Alley, giant hailstones rain down on National Geographic explorer Tim Samaras.
EDITOR'S NOTE: Along with his son, Paul, and storm chaser Carl Young—his longtime collaborators—National Geographic explorer and storm chaser Tim Samaras died in a tornado in El Reno, Oklahoma, on May 31, 2013. He devoted his life to unlocking the mysteries of extreme weather.