Heavy rains from a storm system sparked flash flooding that turned deadly across portions of the Southeast on Sunday and may have also contributed to a freight train derailment.

Flash flood warnings were posted in New Orleans and surrounding areas until 1 p.m. on Sunday as strong storms moved through the area. The National Weather Service's Storm Prediction Center said there was still the risk of "excessive rainfall from parts of the Central Gulf Coast to the Central Appalachians/Mid-Atlantic."

"Showers and thunderstorms will linger along the Eastern Gulf Coast and parts of Florida through Tuesday morning," the NWS said. "Rain will also develop over parts of the Lower Great Lakes/Ohio Valley into the Northern mid-Atlantic and parts of the Northeast."

STORMS DAMAGE ARKANSAS APARTMENTS, LEAVE DAMAGE IN SOUTH

Heavy rain over the past couple of the days has contributed to rising river levels in Louisiana and Mississippi.

"We've had so much rain this week, especially areas of Kansas, parts of Oklahoma, and then right here across areas of the Southeast, Texas, much of Louisiana, Mississippi; it's caused incredible flooding," Fox News Chief Meteorologist Rick Reichmuth said on "FOX & friends."

In Pearl River County, Miss., emergency officials told FOX8 that heavy rains washed out roads and caused the deaths of two people in separate traffic accidents.

The floodwaters also caused at least two bridges to wash out in the county, according to officials.

“It’s been a mess today,” Dudley Russ with the Pearl River County road department told FOX8.

HOUSTON RAIN, FLOODWATERS PROMPT RESCUES AS HUNDREDS LEFT STRANDED

Flooding caused the Mississippi Highway Patrol to close part of Highway 49 in Stone County Sunday morning. The flooding may also have contributed to the derailment of a freight train near Lumberton a little after 7 a.m. Saturday.

The derailment, in Pearl River County, happened as the train traveled from Birmingham, Ala., to New Orleans, Norfolk Southern spokeswoman Rachel McDonnell Bradshaw told the Associated Press. Three of the cars were carrying steel and 25 were empty, Bradshaw said. She said no hazardous materials were involved and no injuries were reported.

The cause of the derailment is under investigation, but WLOX-TV quoted authorities as saying the roads near the derailment were flooded over.

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Mississippi Gov. Phil Bryant said Sunday on Twitter that he had signed a state of emergency declaration for all areas affected by the storms.

The storms also caused power outages. As of about 9:40 a.m., several thousand Entergy customers were without power across Orleans, Jefferson, St. Charles and East Baton Rouge parishes.

The Associated Press contributed to this report.