America's Deadliest Tornado

A man carries a young girl who was rescued after being trapped with her mother in their home after a tornado hit Joplin, Mo. on Sunday evening, May 22, 2011. The tornado tore a path a mile wide and four miles long destroying homes and businesses. (AP Photo/Mike Gullett)

Emergency vehicles line up along northbound Rangeline Road in Joplin, Mo. after a tornado swept through the city in Joplin, Mo. on Sunday evening, May 22, 2011. (AP Photo/The Joplin Globe, Roger Nomer)

Damaged vehicles litter the parking lot of St. John's Hospital in Joplin, Mo, after a tornado hit the southwest Missouri city on Sunday evening, May 22, 2011. A massive tornado blasted its way across southwestern Missouri on Sunday, flattening several blocks of homes and businesses in Joplin and leaving residents frantically scrambling through the wreckage. (AP Photo/Mike Gullett)

A shelf cloud containing a thunderstorm approaches a tornado ravaged neighborhood in Joplin, Mo., Monday, May 23, 2011. A large tornado moved through much of the city Sunday, damaging a hospital, hundreds of homes and businesses and killing at least 89 people. (AP Photo/Charlie Riedel)

Rescue workers in lime green jackets search for bodies and survivors inside St. John's hospital in Joplin, Mo., Monday, May 23, 2011. The hospital was damaged by a tornado that destroyed nearly 30 percent of the city on Sunday afternoon. (AP Photo/Tulsa World, Adam Wisneski)

People climb over wreckage in a neighborhood near St. John's Regional Medical Center in Joplin, Mo. Monday, May 23, 2011, a day after it was hit by a tornado. Authorities warned Monday that the death toll could climb as search and rescue workers continued their efforts. (AP Photo/The Wichita Eagle, Jaime Green)

This frame grab from video shows a massive tornado on Sunday, May 22, 2011, outside Joplin, Mo. The tornado tore a 6 mile path across southwestern Missouri killing at least 89 people as it slammed into the city of Joplin, ripping into a hospital, crushing cars like soda cans and leaving a forest of splintered tree trunks behind where entire neighborhoods once stood. (AP Photo/tornadovideo.net)

Josh Ramsey looks through the rubble of what is left of his mother in law's home following a tornado Monday, May 23, 2011, in Joplin , Mo. A massive tornado that tore a six mile path across southwestern Missouri killed at least 89 people as it smashed the city of Joplin, ripping into a hospital, crushing cars like soda cans and leaving behind only splintered tree trunks where entire neighborhoods once stood. (AP Photo/Jeff Roberson)

Candice Kell, 17, looks over her psychology textbook inside her grandmother's home in Joplin, Mo., Monday, May 23, 2011 after it was damaged by a tornado that destroyed nearly 30 percent of the town on Sunday afternoon. Kell and her grandmother, Jean Logan, rode out the storm in the laundry room. The twister cut a six mile path through the city. (AP Photo/Tulsa World, Adam Wisneski)

Rows of damaged homes are seen following a tornado Monday, May 23, 2011, in Joplin , Mo. (AP Photo/Jeff Roberson)

Tornado damage is seen Monday, May 23, 2011, in Joplin, Mo. A large tornado moved through much of the city Sunday, damaging a hospital and hundreds of homes and businesses and killing at least 89 people. (AP Photo/Jeff Roberson)

Residents of Joplin, Mo, survey the damage of their homes and city on Monday, May 23, 2011. A tornado that struck Joplin, Mo, on Sunday, May 22, killed at least 89 and injured hundreds more. (AP Photo/Mike Gullett)

Coworkers Cindy Albers, left, and Kim Hoosier hug on 20th Street near New Hampshire Ave in Joplin, MO., Monday, May 23, 2011. A large tornado moved through much of the city Sunday, damaging a hospital and hundreds of homes and businesses and killing at least 116 people. (AP Photo/ The News Leader, Valerie Mosley)

Dylan Womack recovers a a spine model from Skagg's Chiropractic in Joplin, MO., Monday, May 23, 2011. A large tornado moved through much of the city Sunday, damaging a hospital and hundreds of homes and businesses and killing at least 116 people. (AP Photo/ The News Leader, Valerie Mosley)

Meghan Miller stands in the middle of a destroyed neighborhood as she checks on her sister in law's home Monday, May 23, 2011, in Joplin , Mo. A large tornado moved through much of the city Sunday, damaging a hospital and hundreds of homes and businesses. (AP Photo/Jeff Roberson)

U.S. President Barack Obama makes a statement to reporters about tornado damage in the United States at Winfield House in London, Tuesday, May 24, 2011. (AP Photo/Charles Dharapak, Pool)

Search and rescue teams fan out across destroyed Joplin neighborhoods on Tuesday morning, May 24, 2011. Rescue crews worked through the rain soaked chill of night, ignoring lightning and strong winds to dig through splintered homes, crumpled businesses and crushed cars in Joplin. (PAP Photo/Robert Ray)

Members of Missouri Task Force One search and rescue team stand by as heavy equipment moves debris from a tornado damaged Home Depot store Tuesday, May 24, 2011, in Joplin , Mo. A large tornado moved through much of the city Sunday, damaging a hospital and hundreds of homes and businesses. (AP Photo/Jeff Roberson)

Members of Missouri Task Force One search and rescue team search a tornado damaged Home Depot store Tuesday, May 24, 2011, in Joplin , Mo. A large tornado moved through much of the city Sunday, damaging a hospital and hundreds of homes and businesses. (AP Photo/Jeff Roberson)

This image taken from aerial video shows damage to St. John's Medical Center in Joplin, Mo. Monday, May 23, 2011, a day after a half mile wide tornado killed at least 116 people when it blasted much of this Missouri town off the map on Sunday. (AP Photo/newson6.com)