Powerful storms tearing a path of destruction across several U.S. states have killed at least 20 people, many of them in Indiana where two small towns were reduced to rubble.
Authorities reported fatalities in Indiana, Kentucky and Ohio Friday as several dozen tornadoes touched down from the Gulf Coast to the Great Lakes.
A huge band of storms tore roofs off homes, damaged buildings and flipped over tractor-trailers, leaving rescue crews scrambling to find survivors among the debris.
Dozens were hurt, some seriously, and it wasn't immediately clear how many people were missing.
Forecasters said the fast-moving storms put 10 million people at risk.
"We knew this was coming. We were watching the weather like everyone else," Clark County, Ind., Sheriff Danny Rodden told The Associated Press. "This was the worst case scenario. There's no way you can prepare for something like this."
The town of Marysville, home to 1,900 people in the southern part of Indiana, is "completely gone," the sheriff's office said.
Severe damage was also reported in the nearby town of Henryville, with a population of about 2,000.
AP reports that a middle school in Henryville was in session when a tornado ripped off the second floor of the building. Miraculously, only minor injuries were reported.
The howling winds scattered debris to the northeast, where the Cincinnati-Northern Kentucky International Airport had to close briefly because junk was landing on the runways.
The storm system was causing problems and damage in other U.S. states, including Alabama and Tennessee. At least 20 homes were badly damaged and six people were hospitalized in the Chattanooga, Tenn.
Further east, Blaine Lawson and his wife Billie were watching the weather when strong winds ripped the roof off their home. They weren't hurt.
"It just hit all at once," said Lawson, 76. "Didn't have no warning really. The roof, insulation and everything started coming down on us. It just happened so fast that I didn't know what to do. I was going to head to the closet but there was just no way. It just got us."
A maximum security prison about 10 miles from Huntsville, Ala, was also damaged, but none of the 2,100 inmates were injured and no one escaped, a corrections department spokesman said.
The latest storm comes just two days after tornadoes killed 13 people in the Midwest and the South.
Forecasters at the National Weather Service's Storm Prediction Center in Oklahoma said they issued the highest risk level warnings for Friday's storms.
Such warnings are issued only about five times a year, they said.
Severe thunderstorms with the threat of tornadoes were predicted in a large swath of the country, crossing a region from southern Ohio through much of Kentucky and Tennessee.
Tornado watches were also issued in parts of Missouri, Illinois and Indiana. Forecasters blame the storm system on humid, unstable air streaming north from the Gulf of Mexico.
