A deadly storm system that spawned tornadoes in Gulf Coast states Tuesday night was expected to bring severe weather to the Carolinas on Wednesday afternoon.

Around 3 p.m. ET Wednesday, the U.S. National Weather Service issued tornado watches on Twitter for parts of Maryland, North Carolina and Virginia. Subsequent tornado warnings were issued for several locations in the latter two states.

The Tuesday storms mangled trailers at an RV park, ripped roofs from buildings and killed at least three people in Louisiana and Mississippi, authorities said.

One of the hardest-hit areas in the Gulf Coast appeared to be a recreational vehicle park in the town of Convent, in southern Louisiana. Two people were killed there, said St. James Parish Sheriff Willy Martin, speaking on local television. Authorities were working into the early morning to look for people possibly trapped under the debris, Martin said.

Thirty-one people were taken to area hospitals and seven of them were in critical condition, he said.

"We never had anything like this; we never had this many people injured in one event, and so much destruction in one event," Martin told WVUE news. "We won't stop searching until we're satisfied we've searched every pile."

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Debris from a damaged water tower is shown in this handout photo provided on Wednesday by Assumption Parish Sheriff's Office, west of New Orleans, La. (Assumption Parish/Reuters)

Martin said three people were still believed to be missing but efforts to account for them were hampered because authorities didn't know how many people were at the park when the storm hit or how many people were taken to hospitals in private vehicles.

Jerome Picou, who lives near the park, said just before the tornado hit that it was raining and the skies grew dark. Then he heard what sounded like a freight train.

"The wind was blowing a little bit, but then it stopped. Then all of a sudden all kinds of wind and rain started. It was so bad, I had to go inside the house or I would have been blown away with it," Picou said.

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One of the tornadoes tore through this RV park in the town of Convent, in southern Louisiana. (David Grunfeld/NOLA.com The Times-Picayune via AP)

In Alabama and Georgia, forecasters issued flash flood watches ahead of the storm system, which was expected to drop up to five centimetres of rain. The warnings were expected to be in effect through Wednesday afternoon. The northern part of Georgia was also under a wind advisory.

The Wednesday forecast for the Carolinas calls for possible flash flooding and severe thunderstorms, including damaging winds, hail and isolated tornadoes.

Raleigh forecasters said straight-line wind gusts may be particularly strong, reaching 110 kph or greater.

News outlets in Georgia, South Carolina and Florida reported that schools in those states canceled Wednesday classes ahead of the storm threat.

In Mississippi, officials Tuesday night were sorting through reports of damage to some buildings. Local media reports said a 73-year-old man died in Lamar County after a tornado destroyed his double-wide mobile home.

Tornado also confirmed in Florida

The reported tornadoes are part of a line of severe weather and storms that ripped through the region.

South Severe Weather

Florida Gov. Rick Scott, centre, tours a destroyed apartment complex in Pensacola, Fla., on Wednesday after a powerful storm affected the area. The U.s. National Weather Service is surveying the damage to determine if it was caused by a tornado. (Tony Giberson/Pensacola News Journal via AP)

At least seven tornadoes hit southeast Louisiana and southwest Mississippi, said Ken Graham, the meteorologist in charge for the National Weather Service's southeast Louisiana office.

That number includes the one in Convent and near Purvis, Mississippi, he said. Teams will be sent out in the morning to document the damage and rate the tornadoes, he said.

The harsh weather even affected the National Weather Service, Graham said. At one point the staff in the Slidell office took shelter because a tornado was nearby, and lightning took out the office's radar, forcing them to use backups, he said.

"We felt the shockwave go through the building," Graham said.

In Florida, the National Weather Service said a tornado hit Pensacola. Meteorologist Steve Miller said the service has had many reports of property damage and people injured in storms Tuesday night.

Reported tornadoes and severe weather caused damage in other parts of both states.

A reported tornado caused some damage but no injuries near New Orleans' main airport, while high winds ripped off roofs and downed trees around the greater New Orleans area. Other suspected tornadoes were reported north of Lake Pontchartrain and west of the city in St. Charles and Ascension parishes and in Prairieville, between New Orleans and Baton Rouge, heavy damage was reported to some buildings, including a fitness gym.

Ronald Myers lives across the street from New Mount Bethel Baptist Church in Kenner, La., just outside of New Orleans. He recalled the sky darkening and high winds — he believes it was a tornado. He and his wife came outside when they heard the church's alarm go off. High winds sheared the brick and mortar from the rear wall of the church.

"My wife came over to turn the alarm off and she came back home and said, `Baby, the wall behind the church has done fell down,"' said Myers. He said he struggled to keep his footing in the wind, and it nearly knocked his wife down.