A terrifying warning that a dam could collapse and unleash 17-foot-deep floods has forced an evacuation overnight in Lynchburg, Virginia. The College Lake Dam has not yet failed but is being closely monitored by emergency personnel for any signs of structural failure, CNN reports. The dam exceeded its capacity after as much as six inches of rain fell Thursday evening. A flash-flood warning issued Thursday night by the National Weather Service warned: “If a complete failure of the dam occurs, the water depth at Lynchburg could exceed 17 feet in seven minutes.” The city of Lynchburg lies one mile downstream from the dam. It has a population of about 80,000 and some 124 households have been urged to evacuate, Lynchburg’s Department of Emergency Services said. The CNN Weather Center forecast one to three additional inches of rain through Friday evening.