Powerful storms have caused extensive damage in the southern and midwestern region of the United States, with at least 15 lives lost. Rescue workers and police searched for victims in the rubble and treated dozens of injured people. Deaths were reported in Texas, Arkansas, Oklahoma, and Kentucky, according to US media on Sunday. Tornadoes were reported in many places overnight on Saturday. US media reported hailstones that were about the size of tennis balls. According to initial estimates, one of the storms in Oklahoma reached at least level three out of five. Tornadoes of this classification…