Eye Opener: Multiple tornadoes cause destruction across several states / Midwest Braces Amid Threat from Pounding Winds, Hail and Tornadoes / Tornadoes remain a deadly mystery -- and researchers are fighting against time to save lives / Upper Midwest braces for severe weather with the potential for strong tornadoes / Tornadoes, Giant Hail, and Damaging Winds Set to Rip Through the Upper Midwest Today / Tornado formation is still a mystery in the weather world. Researchers are fighting against time to save lives / Why so many tornadoes hit tornado alley / At least 16 dead in flooding and tornadoes as storms slash from Texas to Ohio / At least 19 dead after storms bring flooding and tornadoes to parts of US / At least 16 dead in flooding and tornadoes as storms slash U.S. South and Midwest