The first wave of a weather system that hit south Louisiana on Wednesday morning brought widespread flooding from Lake Charles to southeast Louisiana and at least one death believed caused by the storm.

The River Parishes were particularly hard hit, with some areas receiving almost 10 inches of rain.

Roads were closed, homes flooded, sandbags were flying out of the Lamar-Dixon Expo Center in Gonzales to try to keep up with rising water, caskets in Assumption Parish floated out of the ground, a tornado touched down in Garyville and one man was killed when he apparently slipped in fast-moving water north of Gonzales.

And it’s not over yet. More rain is expected over the next few days.

In Ascension Parish, 56-year-old Danny Deville, of Melville, was found dead under his truck in his employer’s flooded parking lot. Sheriff’s deputies said they believed he slipped and fell into swiftly moving water that swept him under the vehicle.

“Water was flowing swiftly across the parking lot, and the water was probably 12 to 18 inches deep,” Chief Deputy Tonu Bacala said in a news release.

Deville’s employers, who have a business on Babin Road in the Duplessis area of Ascension north of Gonzales, had decided to let their employees to go home at about 11 a.m. because of rising flood water, Bacala said.

Nearly six hours later, at 4:50 p.m., a supervisor found Deville under the pickup.

In St. James Parish, Mark Bourgeois woke up around 6:30 a.m. to water rushing into his home just off River Road in Paulina. By the time local officials began providing sandbags for the community at 11 a.m., it was too late.

Bourgeois and his family watched as 5 inches of water crept into the house before levels finally began to taper off and recede hours later.

This is the third time Bourgeois’ home flooded in the half century his family has been on the property, despite what he claims to be one of the highest elevations in the parish. But Wednesday brought some of the highest water he’s ever seen.

“We couldn’t stop it,” Bourgeois said, as he, his family and neighbors helped remove ripped up floors and soaked furniture from his slowly drying home.

Kurt Roussel, chief of the Paulina-Grand Point-Belmont Volunteer Fire Department in St. James Parish, said 8 inches of rain fell in the area over two hours — a record.

St. James Parish President Timmy Roussel said the “water levels are higher than the water levels when (Hurricane) Isaac hit us” in August 2012, then a record year.

Over in Grand Point, Ernie Matherne, 57, said the water started flowing into his grocery store on La. 3125 by 6:30 a.m.

By the time the water was finished rising, Matherne said, there was 8 inches of water and countless damage to the merchandise at Matherne’s Supermarket.

“It was just too much water coming down at one time for the drainage,” said Matherne, who co-owns the four-store chain with his brother, Dale.

Ernie Matherne said he was able to get in the Paulina store by noon Wednesday, and he and others worked to push out the muddy water.

He said he is concerned about weather forecasts indicating more severe weather could be in store Thursday but he said he still planned Wednesday afternoon to reopen his store.

“I’m proceeding as if we’re not going to flood again. If it happens again, we’ll do it again.”

Parish President Roussel said the quickly rising water from the heavy rain flooded at least 75 homes in the Lutcher, Gramercy and Paulina areas.

In Assumption Parish, high water backed up against old railroad tracks and flooded homes, Rose Hill Baptist Church and the nearly 123-year-old church’s graveyard, Rose Hill St. James Cemetery.

Reserve Deputy Scott Domingue said two caskets came out of the in-ground graves, another casket almost came out and 10 other graves floated up out of the ground.

He, other deputies and sheriff’s trusties filled sandbags at a store along La. 308 and drove them 2 miles down Belle Rose Lane to the flooded area to keep the graves from floating up further.

“I’ve been sandbagging since about 11 (a.m.),” Domingue said about 7 p.m. Wednesday.

The Rev. Rodney M. Dugas, pastor of Rose Hill Baptist Church, said similar flooding in the past 20 years has caused graves to float and other damage to the cemetery two other times, again upsetting residents and church members with loved ones in the cemetery.

Sheriff Mike Waguespack said the caskets have been taken to an area funeral home, and deputies are watching the cemetery, as more rain is expected.

In Ascension Parish, East Ascension Drainage Director Bill Roux said all six pumps at the Marvin J. Braud Pumping Station in the McElroy Swamp and the three pumps at a separate station in Sorrento on Bayou Conway have been running since Wednesday morning.

Roux estimated a minimum of 8 to 10 inches of rain fell in Ascension, rivaling what the parish saw from Tropical Storm Allison in 2002. He noted that the Sorrento area and Pelican Point in Burnside were heavily hit and could have had as much as 10 to 11 inches.

Lester Kenyon, parish government spokesman, said flooding has been reported at 29 residences across the parish, including in Prairieville, Darrow, Gonzales, St. Amant, Sorrento and Donaldsonville. He said the St. Jude area near Donaldsonville had the most concentrated number of flooded homes.

Kenyon said two business on La. 73 in the Dutchtown-Prairieville area also reported flooding.

Three public schools also received some water: Ascension Parish Alternative School in Darrow, Dutchtown Primary School and Prairieville Middle School.

Roux said another typical drainage hot spot in northern Ascension, the Bluff Swamp area, is not raising concerns at this point.

He said Ascension and Iberville parishes shut floodgates that control water flow into that swamp in Ascension and nearby Spanish Lake in Iberville on Tuesday. When the gates are left open, the areas collect backwater flooding from Bayou Manchac, which receives drainage from Ascension, East Baton Rouge and Iberville parishes.

Roux said the floodgates were closed while basin had low water levels, so it now has capacity to handle rainfall.

“That should not be a problem, unless it keeps raining over the next few days, but as it stands right now, that should not be a problem,” he said.

In Baton Rouge, most of the area saw only 2 to 4 inches of rain, but more is on the way.

The culprit is a upper-level low in Texas, Arkansas and northern Louisiana that is drawing in wet air from the Gulf of Mexico and creating unstable conditions leading to thunderstorms, rain and at least one confirmed tornado, said Mike Hill, meteorologist with the National Weather Service. The tornado touched down in Garyville, damaging the Marathon refinery.

Angela Graves, spokesperson for the refinery, said they are continuing to assess the damage, but the initial examination showed damage to a cooling water tower that serves part of the plant. As a result, a crude oil unit was shut down, but a second crude oil unit remains operating.

More rain is forecast for Thursday and Friday and could possibly continue into the weekend. How much more rain is hard to tell, Hill said.

“There’s an old saying: “upper-level low, weatherman’s woe,’ ” Hill said. These types of weather systems tend to bring a mixed bag of weather, and it can be difficult to predict what is in store for south Louisiana.

However, long-range forecasts for southeast Louisiana call for about 5 more inches of rain before this system clears out, said Barry Keim, state climatologist. That forecast could change, but it does give an indication that additional rainfall is on the way.

With that additional rainfall, some waterways in south Louisiana were showing much higher stages, according to the Lower Mississippi River Forecast Center. Vermilion River in Lafayette and Carencro were in flood stage by Wednesday. Several rivers in the Hammond and Covington areas were either in flood stage or expected to get to flood stage by Thursday. That could change, depending on just how much rains certain areas of south Louisiana get in the coming days.

Advocate staff writers Amy Wold and Ellyn Couvillion contributed to this report.