As Tropical Storm Barry pushes toward landfall Saturday between Morgan City and Vermilion Bay as an expected Category 1 hurricane, local officials and tens of thousands of residents are eyeing what impact its rains will have on rivers that brought devastating flooding to the region three years ago.
[Update, 10 a.m. Saturday: Barry has been upgraded to a hurricane.]
According to the National Weather Service's latest estimates Friday, the Comite River at Joor Road is expected to be higher than its 2016 level, but the Amite River should run several feet below flood levels seen in the August 2016 flood.
The Comite, at Joor Road, is expected to reach 34.5 feet Monday evening, or about 4 inches higher than the 34.2-foot level seen three years ago, according to weather service predictions. Flood stage is 20 feet.
Other projections released Friday night show the Amite River at Denham Springs reaching 41 feet Tuesday evening. The level is 12 feet above flood stage but more than 5 feet below the record level seen in 2016.
Jay Grymes, chief meteorologist for WAFB-TV, speculated the rainfall might be closer to Tropical Storm Allison, a slow-moving, meandering summer storm that dropped heavy rain on the Baton Rouge area nearly two decades ago.
"We may be looking at something at least, in the broad scale, similar to what occurred in June 2001," he said.
Allison, which hit the Texas coast first but lingered inland before going back into the Gulf and making landfall again, hit Baton Rouge as a subtropical storm. It raised the Amite River at Denham Springs to 38.34 feet. The river also hit 41 feet in 1977 and 1983.
Grymes cautioned that no storm is exactly the same as another.
Barry is expected to have stronger winds than Allison and the 2016 storm and isn't expected to stall over Louisiana as those storms did, though Barry won't be moving so fast either, projected to take about a day to move through Louisiana.
The Weather Service has projected 10 to 20 inches of rain for the region, including in Lafayette, Baton Rouge and New Orleans, with localized maximums that could reach 25 inches over the next few days.
Denham Springs Mayor Gerard Landry said in an interview Thursday that the city's residents are particularly watching the storm's speed, as the difference in rain dumping for several days is large compared with rainfall coming down over a period of hours.
"The other thing we worry about is it if travels north of us, then there's the Amite watershed," he said. "As it moves north of us the danger isn't over because everything drains into the Amite, so that's the other issue we have that a lot of people don't think about."
According to a 2017 U.S. Geological Survey report, the peak Amite River flow at Denham Springs in August 2016 was somewhere between a 100-year and a 500-year-flood, or floods that have a 1 percent to 0.2 percent chance of happening in a given year.
An important benchmark for flood levels in Ascension and lower Livingston parishes, the Amite at Port Vincent is expected to crest at 13.1 feet Wednesday, at a major flood stage. Flood stage for the river is 8 feet. By comparison, the river hit a peak of 17.5 feet at Port Vincent on Aug. 15, 2016.
Bob Jacobsen, the Amite River Basin Commission's contract hydrologist, said it's probably best to view the Weather Service's projections as guidance at this point until large amounts of rain start falling Saturday and Sunday and forecasters can see how much rain is actually falling and how quickly it is falling.
The current estimates showing wide swaths of territory with 10 to 20 inches of rain or more isn't necessarily what will happen as the rainfall is spread more unevenly than the estimates depict.
"We just don't know how widespread the rain is going to be," he said.
He added the one area of worry is in lower Livingston, Ascension and St. James parishes because some storm surge is expected in Lake Maurepas, potentially holding up drainage from those parishes.
Other river forecasts are the following:
- The Amite River at Magnolia will reach minor flood stage overnight Monday, cresting at 49 feet. Flood stage is 48 feet.
- The Amite at Bayou Manchac is also expected to reach a major flood stage of 19.7 feet at 7 a.m. Wednesday. Flood stage for the river is 9 feet. The record is 21.5 feet.
- The Tickfaw River at Holden will also hit moderate flood stage late Tuesday, coming in at 21 feet. Flood stage is 15 feet.
- The Tickfaw at Montpelier will crest at 18.5 feet at 1 p.m. Monday, putting it in the minor flood stage. That’s well above the flood stage of 13 feet.
- The Natalbany River at Baptist will also crest in the minor flood stage, reaching 20 feet at 7 a.m. Monday. Flood stage is 16 feet.
Staff writer Timothy Boone contributed to this report.