Lynchburg, Virginia officials ordered evacuations Thursday in the area of Black Creek Trail over fears of the College Lake Dam will fail in the heavy flooding. Heavy rains have caused rising water and crews are using caution, CBS Roanoke affiliate WDBJ reports.
According to the National Weather Service, the Lynchburg Water Resources Department reported 4 to 6 inches of rain earlier Thursday evening caused the College Lake Dam to fill beyond its capacity. Twelve to 18 inches of water are flowing over Lakeside Drive into Blackwater Creek.
The nearest downstream city from the dam is Lynchburg. The National Weather Service said if complete failure of the dam occurs, "the water depth in Lynchburg could exceed 17 feet in seven minutes."
County officials reported the dam’s "imminent failure" at around 9:30 p.m. They were still looking for signs of structural failure early Friday as water spilling over the dam, threatening about 124 houses in the city of 80,000.
Local fire and police were sending boats to rescue people to area shelters. A flash flood watch was in effect until 11 a.m.
Officials say people who were evacuated may not be able to return to their homes for at least 24 hours, WDBJ reports.
Lynchburg, Virginia, is located in the Blue Ridge Mountains, about 50 miles from Roanoke.
There were also flash flood warnings issued for the Atlanta area, while the East Coast from northern Georgia to central Pennsylvania was under a flash flood watch.
© 2018 CBS Interactive Inc. All Rights Reserved.