How 2011 Became a 'Mind-Boggling' Year of Extreme Weather

Aired: 12/28/2011 | 0:10:32 | Clip
From snowstorms to floods and tornadoes, severe weather wreaked havoc across the United States this year, with 2011 marking far more extreme weather events than a typical year. Hari Sreenivasan discusses the science behind this year of extreme weather with NOAA's Kathryn Sullivan and Weather Underground's Jeff Masters.