Camryn Dean (7) plays in the newly built tornado shelter behind her mother's rebuilt home on May 19 in the heart of what was once nothing but debris and destroyed homes after a tornado hit the neighborhood almost one year ago in Joplin, Mo. (Joe Raedle/Getty Images) #

Thousands of people walk the path of destruction on May 22 in Joplin, Mo. The community is marking the anniversary of an EF-5 tornado that killed 161 people as it cut a wide swath through Joplin a year ago. (Charlie Riedel/Associated Press) #

Dr. Michael Hill (center) and others bow their heads in prayer during a ceremony at the Freeman Hospital East to celebrate the lives of the survivors and victims of the massive tornado that passed through the town a year ago. (Joe Raedle/Getty Images) #

In this composite image (top) Maddie Meek (9) and her mother Dina Meek salvage what they can from her sister-in-law's home after it was destroyed when a massive tornado struck on May 22, 2011 in Joplin, Mo. One year after (bottom) the tornado, the destroyed buildings and rubble have been removed and new homes have been built on May 20, 2012. (Joe Raedle/Getty Images) #

In this composite image (top) armored car courier Josh Beck works on salvaging cash from an ATM which was damaged and tossed approximately 20 feet when a massive tornado passed through the town on May 22, 2011 in Joplin, Mo. One year after the tornado (bottom) the ATM machine and rubble have been removed on May 20. (Joe Raedle/Getty Images) #

Artists Emily Frankoski (left) and Dolores Bilke paint a tornado damaged tree in Joplin, Mo. on May 16. May 22 marks the one year anniversary of a deadly EF-5 tornado that ripped through the town, killing 161 people. The tornado damaged or destroyed about 7,500 homes and 500 other buildings, but the city is now well into a recovery mode that has spurred some segments of the local economy. (Eric Thayer/Reuters) #

Freeman Hospital employees (from left) Nova Beyersdorfer, billing clerk, Dale Stiver, housekeeping manager, and Nancy Long, director of nursing for Freeman Neosho, release a lantern on May 22, 2012 in memory of May 22, 2011 tornado victims, at Freeman Hospital in Joplin, Mo. The tornado killed 161 people and destroyed one-third of the city, making it the nation's deadliest single tornado in six decades. (Roger Nomer/The Joplin Globe via Associated Press) #

Hollyhocks grow in an abandoned garden on May 8 at a destroyed home in Joplin, Mo. Reconstruction continues in the community as the anniversary of an EF-5 tornado that destroyed a large swath of the city and killed 161 people. (Charlie Riedel/Associated Press) #

The Joplin High School sign is seen in front of the rubble of the school after the letters H and E were placed on it reading "Hope" as the town rebuilds from the catastrophic tornado that hit almost one year ago on May 19, 2012 in Joplin, Mo. (Joe Raedle/Getty Images) #

A sign remembering a tornado victim is seen on a street corner on May 22, 2012, in Joplin, Mo. (Charlie Riedel/Associated Press) #

Students show their emotions at the 2012 Joplin High School commencement ceremony inside the Leggett and Plant Athletic Center at Missouri Southern State University in Joplin, Mo. on May 21. (Larry Downing/Reuters) #

U.S. President Barack Obama greets class seniors before he attends the 2012 Joplin High School commencement ceremony inside the Leggett and Plant Athletic Center at Missouri Southern State University in Joplin, Mo. on May 21. (Larry Downing/Reuters) #

This three-photo combo shows a scene taken on May 25, 2011 (top) July 20, 2011 (center) and May 7, 2012 (bottom) shows progress made in Joplin, Mo. in the year after an EF-5 tornado destroyed a large swath of the city and killed 161 people. In the top photo, Beverly Winans hugs her daughter Debbie Surlin while salvaging items from Winans' devastated home which today stands cleared of debris. (Charlie Riedel/Associated Press) #

Codessa Schoonover spends time remembering her grandmother on May 19 as she sits on what remains of the tree in front of the home her grandmother was killed in when a tornado struck almost one year ago on May 22, 2011. (Joe Raedle/Getty Images) #

A sign reading "Hope" is seen on a fence around the rubble of the Joplin High School after one year ago the town was hit by a catastrophic tornado on May 22, 2011. (Joe Raedle/Getty Images) #

This three-photo combo shows a scene taken on May 28, 2011 (top) July 21, 2011 (center) and May 7, 2012 (bottom)showing progress made in Joplin, Mo. in the year after an EF-5 tornado destroyed a large swath of the city and killed 161 people. In the top photo, Patrick O'Banion salvages items from his devastated home in a neighborhood now mostly cleared of debris. (Charlie Riedel/Associated Press) #

A wall is raised on a Habitat for Humanity house May 22, 2012 being built to replace one that was destroyed one year ago after the town was hit by a tornado on May 22, 2011 in Joplin, Mo. The EF-5 tornado left behind a path of destruction along with 161 deaths and hundreds of injuries, but one year later there are signs that the town is beginning to recover. (Joe Raedle/Getty Images) #

A sign is seen on a tornado damaged tree in Joplin, Mo. May 16, 2012. May 22 marks the one year anniversary of a deadly EF-5 tornado that ripped through the town, killing 161 people. (Eric Thayer/Reuters) #

Morgan Osburn (far left) David Hoosier and Kim Hoosier spend a quiet moment on May 20 together in front of a memorial built for their friend Lance Hare who was killed when the town was hit by a massive tornado almost one year ago in Joplin, Mo. (Joe Raedle/Getty Images) #

This three-photo combo shows a scene taken on May 27, 2011(top) July 21, 2011 (center) and May 7, 2012 (bottom) shows progress made in Joplin, Mo. in the year after an EF-5 tornado destroyed a large swath of the city and killed 161 people. In the top photo, Jim Goff carries salvaged items to his car as he helps a friend retrieve items from a destroyed home in a neighborhood now mostly cleared of debris. (Charlie Riedel/Associated Press) #

Construction workers help build a home on May 21at the spot where a home had been knocked down almost one year ago by the massive EF-5 tornado that passed through. (Joe Raedle/Getty Images) #

Mary Black hugs her brother Scottie Black (far left) as Dawna Middleton and Bill Cook also hug during a prayer service in front of the iron cross that is all that remains of St. Mary's church after it was destroyed by the tornado one year ago on in Joplin, Mo. (Joe Raedle/Getty Images) #

A destroyed home is seen in front of a house that is being built in Joplin, Mo. on May 16. May 22 marks the one year anniversary of a deadly EF-5 tornado that ripped through the town, killing 161 people. The tornado damaged or destroyed about 7,500 homes and 500 other buildings, but the city is now well into a recovery mode that has spurred some segments of the local economy. (Eric Thayer/Reuters) #

Scott Hasty places an American flag on May 22 next to where his house was before it was destroyed by the massive tornado that passed through the town one year ago in Joplin, Mo. Hasty said he was in the house when the EF-5 tornado hit leaving behind a path of destruction along with 161 deaths and hundreds of injuries, but one year later there are signs that the town is beginning to recover. (Joe Raedle/Getty Images) #