John Warner surveys the damage near a friend's mobile home in the Steelman Estates Mobile Home Park, destroyed in a tornado, near Shawnee, Oklahoma, May 20, 2013.

A fire burns in the Tower Plaza Addition following a tornado in Moore, Oklahoma, May 20, 2013.

Moore police dig through the rubble of the Plaza Towers Elementary School following a tornado in Moore, Oklahoma, May 20, 2013.

This photo provided by KFOR-TV shows homes flattened outside Moore, Oklahoma, May 20, 2013.

A tornado moves past homes in Moore, Oklahoma, May 20, 2013.

A woman carries her child through a field near the collapsed Plaza Towers Elementary School in Moore, Oklahoma, May 20, 2013.

Seven-year-old Katrina Ash holds a doll as she waits in the back of a truck with her grandfather, Michael Bowen, after a tornado ripped through their neighborhood near Dale, Oklahoma, May 19, 2013.