An excess of rain, sleet and snow spoiled school plans and outdoor activities in the area, but meteorologists believe the inclement weather could result in a different challenge in the Tennessee Valley — flooding.
“We’re concerned about it,” said Trisha Palmer, a meteorologist with the National Weather Service in Peachtree City, Ga. “For the entire Southeast, 10 days without rain has been very rare. The rivers and reservoirs are very high.”
Ms. Palmer said last year’s concluding months, usually a drier time, did not bring the relief the area normally receives.
“We didn’t have the chance for everything to go back to base flow at the end of the fall because it just kept raining,” she said.
That lack of a drying-out period could warrant some real concern about localized flooding around the region, she said.
TOTAL PRECIPITATION* January/February 2006: 7.24 inches* January/February 2007: 4.56 inches* January/February 2008: 7.62 inches* January/February 2009: 7.98 inches* January/February 2010 (through Friday): 9.16 inchesSource: National Weather Service
A less immediate but still threatening issue looms about 100 miles northeast of Chattanooga. The Tennessee River is the runoff area for part of the now snow-capped Great Smoky Mountains — particularly Mount LeConte, the third highest peak in the Smokies and a popular getaway resort. When that snow melts, it will flow downstream toward this area.
“We had 36 inches (of snow) on the ground this morning,” said Bob Miller, spokesman for the park. “If it stays cold and rains a little at a time, it’ll melt slowly, but if all of a sudden it goes 55 or 60 degrees with a bunch of rain on top of that, it could come down the mountain with some force.”
The good news is that Mr. Miller’s report of several feet of snow will not translate into several feet of rain due to the differences in molecular structure, according to Ms. Palmer. Snow molecules contain more air than rain molecules.
Still, she said, it’s smart to be on the lookout because of other factors.
“Here in the Southeast, we often get those snowball-type snows, so it will have a more liquid profile,” Ms. Palmer said.
“If you have a very wet snow, it may only take five or six inches of snow to translate to an inch of rain. We also generally have a lot of moisture around, so there’s more actual water involved (when it melts),” she said.
Rainfall and runoff from 2009 combined with recent precipitation have the Tennessee Valley Authority generating at maximum capacity on nine hydroelectric dams on the Tennessee River and at most of its 20 power-producing tributary dams, TVA spokesman Travis Brickey said.
Couple this with the fact that, as anyone who has lived in Southeast Tennessee or Northwest Georgia knows, residents cannot count on the rain faucet getting turned off anytime soon. March and April — typically wet months — promise to bring more inches of rain than usual this spring, according to Ms. Palmer.
“Everything is high, all the reservoirs are high, and if we get our typical spring rain — which in this case we may get more than typical — we definitely could see flooding problems across the area,” she said.
But Chuck Bach, TVA’s general manager for river scheduling, doesn’t believe a major flood will wreak havoc on the area anytime soon, as several reservoirs will be set for maximum capacity as spring rains arrive.
“With all this rain we got, the river much higher than normal and this time of year, we get a lot of runoff because the grass is dormant, trees are dormant,” he said. “But we’ve held water back in our tributaries. … We’re slowly catching up with everything since it hasn’t rained in the last week.”
As opposed to some recent area droughts, Mr. Bach sees the rainier conditions as a bit more “normal” for the Chattanooga area, a place he said should get about one inch of rain per week. He believes his staff can handle the challenge.
“We don’t anticipate any flooding,” he said. “And we’ve created space so if a storm does come, we can hold that water.”