ATHENS, Ala. (AP) -- Powerful storms stretching from the Gulf Coast to the Great Lakes flattened buildings in several states, wrecked a small Indiana town and bred anxiety across a wide swath of the country in the second powerful tornado outbreak this week.
Widespread damage was reported in southern Indiana, where Clark County Sheriff's Department Maj. Chuck Adams said the town of Marysville is "completely gone." Dozens of houses were also damaged in Alabama and Tennessee two days after storms killed 13 people in the Midwest and South.
No fatalities had been reported in the latest round of storms that were expected to threaten tornadoes late into Friday.
Thousands of schoolchildren in several states were sent home as a precaution, and several Kentucky universities were closed. The Huntsville, Ala., mayor said students in area schools sheltered in hallways as severe weather passed in the morning.
At least 20 homes were badly damaged in the Chattanooga, Tenn., area after strong winds and hail lashed the area. To the east in Cleveland, Blaine Lawson and his wife Billie were watching the weather when the power went out and winds ripped the roof off their home. Neither were hurt.
"It just hit all at once," the 76-year-old Blaine Lawson said. "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."
In the Huntsville area, five people were taken to hospitals, and several houses were leveled by what authorities believed were tornadoes Friday morning. The extent of the people's injuries wasn't immediately known, and emergency crews were continuing to survey damage.
"Most of the children were in schools so they were in the hallways so it worked out very well," said Huntsville Mayor Tommy Battle.
An apparent tornado also damaged a state maximum security prison about 10 miles from Huntsville, but none of the facility's approximately 2,100 inmates escaped. Alabama Department of Corrections spokesman Brian Corbett said there were no reports of injuries, but the roof was damaged on two large prison dormitories that each hold about 250 men. Part of the perimeter fence was knocked down, but the prison was secure.
"It was reported you could see the sky through the roof of one of them," Corbett said.
Authorities are confident that storms that hit Limestone and Madison counties were tornadoes, but it will be up to the National Weather Service to confirm the twisters, said Alabama State Emergency Management Agency spokeswoman Yasamie August.
"We're still getting reports of damage pretty much as we speak," she said at midday.
For residents and emergency officials across the state, tornado precautions and cleanup are part of a sadly familiar routine. A tornado outbreak last April killed about 250 people around the state, with the worst damage in Tuscaloosa to the south.
Forecasters warned of severe thunderstorms with the threat of tornadoes crossing a region from southern Ohio through much of Kentucky and Tennessee. By early Friday afternoon, tornado watches covered parts of those states along with Missouri, Illinois and Indiana.
In Norman, Okla., forecasters at the Storm Prediction Center said they were bracing for what could be a potent tornado outbreak.
"Maybe five times a year we issue what is kind of the highest risk level for us at the Storm Prediction Center," forecaster Corey Mead said. "This is one of those days."
Mead said a powerful storm system was interacting with humid, unstable air that was streaming north from the Gulf of Mexico.
"The environment just becomes more unstable and provides the fuel for the thunderstorms," Mead said.
Schools sent students home early or cancelled classes entirely in states including Alabama, Tennessee, Mississippi, Kentucky and Indiana. In Alabama alone, more than 20 school systems dismissed classes early Friday. The University of Kentucky, the University of Louisville and several other colleges in the state also canceled classes.
In Alabama, at least 10 homes were damaged in a subdivision in Athens. Homeowner Bill Adams watched as two men ripped shingles off the roof of a house he rents out, and he fretted about predictions that more storms would pass through.
"Hopefully they can at least get a tarp on it before it starts again," he said.
Not far away, the damage was much worse for retired high school band director Stanley Nelson. Winds peeled off his garage door and about a third of his roof, making rafters and boxes in his attic visible from the street.
"It's like it just exploded," he said.
Contributing to this report were Associated Press writers Jim Suhr in Harrisburg, Ill., and Jeff Martin in Atlanta, Associated Press videojournalist Robert Ray in Cleveland, Tenn., and AP Radio's Shelly Adler in Washington.