WAVERLY, Tenn. — David Allen was inside his downtown Waverly home with his 84-year-old mother when an air conditioning unit floated by. They made it as far as the porch before, Allen said, water slammed into the door frame, as record-breaking rain and flash flooding swept through the area. Abandoned cars and entire sheds are piled up on a bridge’s guardrails, swept up by water that rose over the roadway. “I would call this a living nightmare and miracle all at the same time,” Lindsey Coplin said. In Waverly, Allen stood outside his home with a friend as they tried to pick up what was left of it.