The 40-acre pond was used by the Tennessee Valley Authority to hold a slurry of ash generated by the coal-burning Kingston Steam Plant in Harriman, about 50 miles west of Knoxville, said TVA spokesman Gil Francis. The dam gave way just before 1 a.m, burying a road and railroad tracks leading to the plant under several feet of dark gray mud.
Authorities said no one was seriously injured or hospitalized.
Investigators were trying to determine exactly what caused the breach, but the TVA spokesman said heavy rains and freezing temperatures may be to blame. Forecasters said the overnight temperature dropped to 14 degrees in Harriman and Francis said there had been 4.9 inches of rain this month so far compared to 2.8 inches in a typical December.
"I am still in shock," said Crystell Flinn, 49, whose ranch-style house was pushed off its foundations and driven more than 30 feet onto a road. "I don't think it really has hit me yet."
Flinn was traveling back from Knoxville when a friend called her cell phone to say she had heard that the flood hit Flinn's house and that her 53-year-old husband James Schean was trapped inside.
Schean escaped cold and shaken but not injured. Flinn told his story while he slept at a temporary shelter at a community college.
Schean, a boilermaker at the TVA plant, was in bed when he "heard a loud clap like thunder," she said. Pieces of the ceiling began falling, wood was popping, glass breaking and furniture falling. And then the house started to move.
"He didn't know what was going on," his wife said. "He couldn't see anything. He had to tear one door off the hinges to get out of the bedroom, and he couldn't get out the front door so he had to kick out a window."
Flinn cried as she looked at aerial photographs of the home, which she and Schean had spent the past 3½ years remodeling and recently filled with Christmas presents.
"I seriously doubt they will let us (rebuild)," Flinn said. After losing another house on the same property to fire 20 years ago, "I am not sure we want to," she said. "The next time we might not make it out."
Emergency workers rescued people from two partially collapsed homes and used four-wheel drive vehicles to help others who couldn't get out of their driveways, said Roane County Rescue Squad spokesman Brian Grief.
Officials originally said 15 homes were flooded, but Francis later said 12 homes had been damaged to some degree. Flinn's house was the worst hit.
Only Flinn's family came to the emergency shelter, which closed later Monday. TVA offered them and others needing help motel rooms.
Francis said 30 pieces of heavy equipment and nearly 100 people were involved in the cleanup effort. He said water flow through a dam on the Clinch River - which flows into the Tennessee River - has been reduced to prevent pollution from runoff from the flood.
Howie Rose, the director of the Roane County Office of Emergency Management and Homeland Security, said a train carrying coal to the plant reached the point on the tracks that was covered in mud and couldn't go forward or back up. He said authorities were trying to assist the train.
The broken dike left about 4 to 5 feet of water and mud over 250 to 400 acres, Francis said. The Environmental Protection Agency was notified.
The pond is used for dumping a slurry of waste from burning coal at the steam plant, Francis said. TVA will check for signs of problems at its 10 other coal-fired plants, most of which were built in the 1950s.
"They're going to look at that for sure, but we have not had one of these (breaks) like this anywhere," Francis said.
Knoxville-based TVA supplies electricity to 8.8 million consumers in Tennessee, Mississippi, Alabama, Kentucky, Georgia, North Carolina and Virginia.