2018 sets record for most rain in Tennessee Valley [photos]

A Tennessee Riverpark pier is flooded as TVA spills water from the Chickamauga Dam on Wednesday, Jan. 2, 2019, in Chattanooga, Tenn. The Tennessee Valley Authority has declared 2018 the wettest year on record for the Tennessee Valley region with 67.1 inches of rainfall, surpassing a previous record of 65.1 inches set in 1973.

A rainy end to December catapulted 2018 into the top 10 wettest years on record, and it didn't stop there.

There was more rain the last two weeks of the year than the Tennessee Valley typically sees in a month - even during the wettest months. That rain, combined with steady storms from spring on, made 2018 the wettest year on record for the Tennessee Valley and one of the wettest years in the history of Chattanooga.

"We got the entire month's average in just the last two weeks," National Weather Service meteorologist Sam Roberts said.

Until then, weather experts and meteorologists expected 2018 to be a top year for rainfall, but not necessarily the top year on record. In mid-December, Tennessee Valley Authority river forecast center manager James Everett said: "As it stands right now, unless we get a real major flood event, it doesn't look like we'll take the top spot."

The area got its major flood event less than a week later.

Nearly 5 inches of rain in Chattanooga from December 14 through New Year's Eve helped push the Tennessee Valley above its record setting year of 1973, which saw 65.1 inches of rain. The utility company tracks weather patterns for the 41,000-square-mile, seven-state Tennessee Valley area and has rainfall data going back 129 years.

"A couple weeks ago, I was kind of disappointed because the forecast had turned dry, and it didn't look like we were even going to get near the record," TVA river forecast center manager James Everett said. "And by New Year's Eve, we have now received 67.01 inches of rainfall."

However, despite that record rainfall in the valley, Chattanooga didn't crack its top 10 wettest years, according to readings at the weather station at the Chattanooga airport. Chattanooga was roughly 13.5 inches above the 52.48-inch average, which made 2018 the city's 13th wettest year of all time.

The National Weather Service has rainfall totals for the Chattanooga airport area dating back to 1879.

"Rainfall amounts vary quite a bit, even between just a couple of miles," Roberts said. "From the airport location, Chattanooga comes in at 13, which is a little misleading because there were several places nearby that did have quite a bit more rain."

Despite placing outside the top 10, Chattanooga is experiencing the effects of the record-setting rain in North Carolina and other areas of the valley.

Heavy rain in the mountains northeast of the city drains into creeks and eventually the Tennessee River, increasing river flow and water levels.

"It's one integrated system, so what happens in the mountains will affect Chattanooga," TVA senior program manager Travis Brickey said.

TVA has opened some of its dams to allow water to pass through, increasing flow rates but ensuring major flooding doesn't devastate the region. The process, known as spilling, reduces the water level to allow the system to take on more water as rainfall continues.

It's the reason the agency drops the river level in the fall.

The high flow rate has stopped commercial traveling on the Tennessee River in the Nickajack Gorge section below Chickamauga Dam. The flow rate Wednesday morning was at more than 900,000 gallons per second. The threshold for commercial travel is 750,000 gallons. TVA leaders hope to have the section reopened to by the weekend.

The year adds to the recent trend of extreme weather conditions in the Southeast. Droughts combined with arson led to major wildfires in 2016. The federal government and climate scientists expect the trend of extreme weather patterns to continue.

As for 2019, rain in the northern part of the Deep South region, which includes Tennessee, is expected to see above normal rainfall, according to The Old Farmer's Almanac 2019.

The almanac predicts the spring and summer will be rainier than normal before a cool fall brings below average rain.

Contact staff writer Mark Pace at mpace@timesfreepress.com or 423-757-6659. Follow him on Twitter @themarkpace and on Facebook at ChattanoogaOutdoorsTFP.