The rubble of a destroyed neighborhood is strewn about a neighborhood in Moore, Okla., Tuesday, May 21, 2013. Many homes were stripped to their foundations Monday by a tornado which moved through the area. (AP Photo/Brennan Linsley)

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This aerial photo shows the remains of houses in Moore, Okla., following the tornado Monday, May 20, 2013. The tornado roared through the Oklahoma City suburbs Monday, flattening entire neighborhoods, setting buildings on fire and landing a direct blow on an elementary school. (AP Photo/Steve Gooch)

In this Tuesday, May 21, 2013 aerial photo, emergency responders make their way down a street of damaged homes following Monday’s tornado. (AP Photo/Kim Johnson Flodin)