It has already been a deadly tornado season in the United States, raising questions about the sophistication of tornado warning systems such as sirens and weather radios.
Michele Norris talks with Nancy Mathis, author of Storm Warning: The Story of a Killer Tornado, about how such warning systems could be improved.
"The average warning time from the National Weather Service is 12 minutes," Mathis says. "That's 12 minutes to figure out where you spouse is, to get the kids, find the pets, figure out where you want to go."
Almost 200 tornadoes have been reported across the country this year, including one that tore through Enterprise, Ala., collapsing a roof at the local high school. Another tornado system in central Florida killed more than 20 people in the middle of the night.