In a runner-up image by U.S. photographer Sean Heavey, a supercell thunderstorm roars across a prairie in Montana. These colossal storms include mesocyclones, rotating updrafts that can deliver torrential rain and tornadoes, according to NASA.

http://news.nationalgeographic.com/news/2010/12/photogalleries/101216-national-geographic-photo-contest-best-pictures-2010/#/national-geographic-photography-contest-honorable-mention-nature_30479_600x450.jpg