Uncommon type of storm causes flooding across East Tennessee, with some rescues in Knoxville

The storm that camped out above Knoxville overnight Wednesday into Thursday was an unusual formation that produced drastic flooding — in certain neighborhoods but not others.

Glenn Carrin, a hydrologist at the National Weather Service, said the storm was “definitely not common” because it stayed put over Anderson and Knox counties, creating a full night of thunder and lightning instead of passing through like a typical system.

Just outside the edges of that redeveloping storm, Carrin said, the rainfall totals were small in comparison. Powell, for instance, had over 6 inches of rain but nearby neighborhoods had just 2, he said.

“The vast majority fell during the early evening during the first wave,” he said. “(The storm) kept forming over the same area ... for several hours before the main line came through.

“For a system to be that persistent for that long with that much thunder and lightning is not common,” he said. “It’s not unprecedented, but it’s not common.”

Carrin said a similar system dumped 8 inches of rain on the other side of the Great Smoky Mountains in Marble, North Carolina, which caused flooding.

The night of unending rain left parts of Anderson and Knox counties flooded as the sun rose, leaving many roads impassable.

The National Weather Service warned of swelling creeks and the rising waters required at least a handful of evacuations and four vehicle rescues along Pop Hollow Road in Anderson County.

“If you do not have to get out, please don’t," Mayor Terry Frank said in a statement Thursday morning. "If you must leave your home, please use extreme caution and do not drive through floodwaters."

The Knoxville Police Department shared a shocking video Thursday of flooding on 23rd Street in the Fort Sanders neighborhood. Knoxville Fire Department crews had to rescue four people from their apartment. No injuries were reported, KPD spokesman Scott Erland told Knox News in a text message.

The Knoxville Police Department listed a number of roads that were closed in the morning. All but Grand Avenue at 23rd Street have been reopened.

As for damages, the intersection of Central and Irwin streets needed to be repaved due to asphalt failures.

Knox County Highway Director Jim Snowden told Knox News downed power lines caused multiple road closures. Some roads will reopen once utility companies reset the power, he said. All roads should be reopened by the end of day. 

To report flooded roads in Knoxville, call the city at 865-215-4010. 

The National Weather Service said showers should end by early afternoon across East Tennessee, but localized flooding has been reported across the region. Flash flooding is still possible because of the amount of rainfall that accumulated overnight.

“Isolated damaging wind gusts are still possible,” the National Weather Service in Morristown warned.

The National Weather Service said parts of Pigeon Forge received up to 2 inches of rain, causing streams to rise. While some Sevier County residents have shared images of flooding on social media, Sevier County dispatch told Knox News around 9:30 a.m. that no flooding incidents had been reported in the past hour.

As the weekend arrives, dry weather will move in but dangerously high temperatures will send heat index values into the 100s.

This article originally appeared on Knoxville News Sentinel: Knoxville floods: Storms over East Tennessee lead to closed roads