Rains from Hurricane Nicholas spread across southern Louisiana on Tuesday, interrupting the region's cleanup from Hurricane Ida and threatening to bring flash flooding to a saturated area that's well beyond its typical precipitation total for the year.
Nicholas came ashore overnight in southeastern Texas and drifted slowly toward the east. Its eye wasn't expected to cross into Louisiana until Wednesday, but heavy rainbands pelted the Baton Rouge area throughout Tuesday. As night fell, a network of weather hobbyists sharing data with Weather Underground reported rainfall totals generally in the 2½- to 3½-inch range.
With little movement in the upper atmosphere to steer the storm away, heavy rains could continue into Thursday, though the greatest threat was expected by midday Wednesday. Most areas would see 4 to 10 inches of rain, though locally higher amounts pushing 20 inches could cause "life-threatening" flash flooding.
"One of the most distressing parts of this is that the heaviest rain now is expected to fall in the areas that were most devastated by Hurricane Ida," said Gov. John Bel Edwards, who declared an emergency before the storm's arrival. "Obviously this is not what we would want to have happen in Louisiana."
Hannah Lisney, a meteorologist with the National Weather Service's Slidell office, said the rain could fall at rates of 2 to 3 inches of per hour during the heaviest periods.
A flash flood watch was posted for the area through Thursday morning. The ground has seemed perpetually moist this year, with Baton Rouge passing its annual rainfall total of 61.94 inches a month ago. Through midnight Monday — before Tuesday's rain — Baton Rouge was at 66.24 inches for 2021.
Hurricane Ida hit southeastern Louisiana on Aug. 29, and its storm surge, heavy rains and high winds damaged thousands of buildings in nearly every parish east of the Mississippi and Atchafalaya rivers.
While most Ida-caused power outages have largely been resolved, 95,000 remain. Nicholas had already caused 13,500 power outages by Tuesday afternoon, and the new storm's heavy downpours pose an additional threat.
Edwards noted at a news conference that many residents are living in homes that haven't "been temporarily repaired to the point where they can withstand rain."
Debris-choked streams still uncleared after last month's hurricane could also hold the fresh runoff back, potentially putting water into homes that haven't seen it before.
“Please remain vigilant throughout the week as East Baton Rouge Parish may experience excessive rainfall," said East Baton Rouge Mayor-President Sharon Weston Broome.
She cautioned people to not drive on flooded roads or around barricades, and to "check on your family, friends, and neighbors who might still be recovering from Hurricane Ida." She also said city-parish buildings, including community centers, wouldn't open Wednesday.
Mike Efferson, a meteorologist in the NWS Slidell office, said Tuesday that forecasters are more concerned about rapidly rising street flooding than they are about rivers in the Baton Rouge metro area. The Amite and Comite rivers were fairly low before Nicholas' arrival, but the projected rainfall totals are still impressive.
Forecasters said there was no reason to expect a repeat of 2016, when more than 2 feet of rain fell north of the city and swelled many local rivers to record levels.
"I just want to remind you that it wasn’t even a named storm in 2016 that caused massive flooding across most of the state of Louisiana," Edwards said.
Monday night, the Gardere area saw about 5 inches of rain, Efferson said. It and other neighborhoods could see serious flash flooding if there's a repeat, particularly if there are backed-up drains. Parts of Baton Rouge suffered through flash floods during a storm in May.
Tuesday's rains forced a halt to some clean-up efforts in the region, and hard-hit Tangipahoa Parish postponed bringing students back to campuses for the first time since their Ida-forced shutdown.
“Due to the rain and potential flooding expected from Hurricane Nicholas and the interruption of repairs to our buildings due to heavy rains, we will not reopen our schools this week as planned,” the district said. It had hoped to bring students back in a "staggered" reopening beginning Wednesday.
Debris contractors collecting waste from Hurricane Ida in Ascension and East Baton Rouge parishes temporarily suspended their rounds so crews could focus on clearing out blockages that might hold back Nicholas-caused flooding. Tangipahoa Parish President Robby Miller told residents that if they’ve flooded before, it’s likely to happen again.
“We encourage anyone who has had an issue with flash flooding or flooding following extended rain … to please come out and get sandbags,” he said. Those in low-lying areas should evacuate, too, he said.
“I know this comes at a really tough point for a lot of residents, but we’ve got another storm to prepare for and monitor closely," he said.
At its arrival Tuesday, Nicholas hit a region hammered by Hurricane Harvey in 2017. More than a foot of rain fell in the Houston area Tuesday, and 14 inches was reported by mid-afternoon in Galveston.
Harvey inundated southeastern Texas with more than 60 inches of rain across a four-day span four years ago. Southwestern Louisiana suffered through flooding, too.
Nicholas will track over a region still recovering from recent major storms — Laura and Delta last year and Ida two weeks ago.
Parts of Louisiana are saturated with nowhere for the extra water to go, so it will flood, University of Miami hurricane researcher Brian McNoldy said.
“It’s stuck in a weak steering environment,” McNoldy said Tuesday.
So while the storm itself may weaken, he added, “that won’t stop the rain from happening. Whether it’s a tropical storm, tropical depression or post-tropical blob, it’ll still rain a lot and that’s not really good for that area.
Staff writer Paul Cobler and The Associated Press contributed to this report.