A passing storm cell Friday night dropped an estimated 7 inches of rain in two to three hours, causing street and house flooding in northeastern Ascension Parish, federal weather forecasters and local officials said.

On Saturday, social media posts showed flooded streets and yards in the growing section of Prairieville and Galvez.

Ascension Parish President Clint Cointment said he and some council members and officials were driving in the eastern Prairieville and Galvez areas on Friday and Saturday assessing damage from the intense rain.

Several older neighborhoods, such as Rhonda Place, Old Hickory and Chateau Galvez, were affected, he said.

"It was shocking, and it came down in such an intensity that it just overwhelmed the drainage system completely," he said. "It's just not built for that." 

Cointment said parish officials were trying to get an accurate count of how many homes flooded, but, with the July 4 break, he expected that gathering that information wouldn't begin in full force until Tuesday. 

Still, he said the damage information will be critical to assessing what happened and why and urged residents to report in any damage. Much of the water had already dissipated by mid-day Saturday, though more rain was expected. 

In statement later on Saturday, parish officials urged residents to report their damage at http://www.damage.la.gov.

The website through the Governor's Office of Homeland Security and Emergency Preparedness asks questions about location and extent to damage and will accept photographs, parish officials said.

Because the rains in Ascension were not a named storm, the website will default to "other" when "Ascension Parish" is entered, officials added.

Friday night's rain is the second time in less than two months that relatively short, but intense rains have sparked unexpected street and house flooding in Ascension Parish.

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In mid-May, sharp rains dropped nearly 14 inches in six to eight hours in the Bluff Swamp area of northwestern Ascension and southern parts of East Baton Rouge Parish, flooding an estimated 160 homes in Ascension and more than 1,200 homes and businesses in East Baton Rouge.

Brigette Lim, National Weather Service meteorologist in Slidell, said radar estimates show 7 inches fell in eastern Prairieville over a two- to three-hour period starting around 7 p.m. Friday.

Gauge data is limited in parts of the most affected area but a gauge at Muddy Creek in Prairieville hit 5.3 inches over the 24-hour period ended 7 a.m. Saturday, Lim said.

A gauge at Henderson Bayou, which is the Galvez/Lake area, had 3.52 inches, while Welsh Gully, which is in a more central northwestern part of Prairieville, had 2.88 inches, according to data from Lim. 

Lim said the rain fell during a pattern of thunderstorms that had the potential for high rainfall rates.

Cointment said a series of recent flash flooding events over the past year or so highlight the need for a change in drainage and development standards because the more potent storms appear to becoming the new normal.

"That's what we've got to start preparing for. We can't say, 'The system can't handle it,' and just walk away. No, you've got to adapt your system to the new normal," he said.

Even without the adjustment to apparently changing weather patterns, Cointment asserted the parish is decades behind on its drainage infrastructure anyway and needs to catch up.

The Parish Council has adopted a nine-month moratorium on new development to make many of those changes.

Though the East Ascension drainage district board narrowly voted Monday to remove Cointment as director of drainage, he remains in charge for 60 days after the vote under the terms of the now terminated agreement between parish government and the district, a parish attorney said.

The district board has appointed former drainage director and public work official Bill Roux as the interim director.


Email David J. Mitchell at dmitchell@theadvocate.com

Follow David J. Mitchell on Twitter, @NewsieDave.