This story was updated at 4:51 p.m. on Wednesday, Feb. 5, 2020, with more information.
Southeast Tennessee and North Georgia counties are in a flash flood watch until Thursday evening.
A flash flood warning had been issued for southern Hamilton and southeastern Marion counties, according to the National Weather Service in Morristown, Tennessee.
The warning was in effect until 4:45 p.m. EST and 3:45 p.m. CST. Thunderstorms have produced heavy rain across the warned area, NWS reports. Between one and two inches of rain have fallen over the last 3 hours. Flash flooding is already occurring.
With anywhere from a half inch up to 5 inches of rain forecast across the Tennessee Valley, TVA has opened up its spillways at each of its nine mainstream dams on the Tennessee River to limit flooding in low-lying areas across the region.
At the Chickamauga Dam in Chattanooga, 69,479 cubic feet per second — or nearly 31.2 million gallons a second — is flowing through the hydroelectric generators and the spillways Wednesday to help lower Chickamauga Lake levels. At the Nickajack Dam in Marion County, TVA is spilling or generating power with 55,424 cubic feet of water per second — or nearly 24.9 million gallons a second.
"We're holding back quite a bit of water in our tributaries, which we will work to move downstream later when it is safe to do so," TVA spokesman Jim Hopson said.
The only area in the Tennessee Valley flooded Wednesday is in the low-lying farmland and surrounding areas near Savannah, Tennessee below Pickwick Dam which had some minor flooding.
"We'll know a lot more tomorrow (Thursday) once we know how much rainfall we actually get in our area," Hopson said.
TVA expects most of the rain Wednesday will be in the higher elevation areas of eastern Tennessee, including on the Ocoee, Hiwassee and Douglas watersheds, Hopson said.
According to Weather.gov, a flash flood warning is issued when a flash flood is imminent or occurring. If you are in a flood prone area move immediately to high ground. A flash flood is a sudden violent flood that can take from minutes to hours to develop. It is even possible to experience a flash flood in areas not immediately receiving rain.
A flood watch is issued when conditions are favorable for a specific hazardous weather event to occur. A flood watch is issued when conditions are favorable for flooding. It does not mean flooding will occur, but it is possible.
All Bradley County Schools dismissed 30 minutes early Wednesday due to "rising waters," as well.