Relentless wind and rain continued to pummel large swaths of the US South on Tuesday, causing tornadoes, sparking a flash flood emergency in Alabama and damaging homes from Texas to Virginia.

The National Weather Service (NWS) issued the flash flood emergency for the Birmingham, Alabama area at the start of rush hour, warning that torrential rains — as much as five inches in some areas — had already fallen and another two inches were possible before the storm system continued moving east.

Jefferson County Emergency Management officials urged residents to stay off the roads because so many were flooded.

Strong winds blowing behind a line of storms were toppling trees across central Alabama, where soil was saturated with water.

In the Birmingham suburb of Homewood, residents huddled on the second-floor balcony of an apartment complex that became flooded.

Severe Weather Mississippi
Carol and Billy Poore try to salvage items from their Yazoo City, Mississippi home after it was heavily damaged by severe weather (Barbara Gauntt/The Clarion-Ledger via AP)

Rescuers in a small boat paddled through the parking lot past submerged cars.

Parts of Louisiana, Mississippi, Alabama and Tennessee, as well as corners of Arkansas and Georgia were at enhanced risk for the worst weather, according to the national Storm Prediction Centre.

That zone is home to more than 11 million people and includes the cities of Nashville, Tennessee; Birmingham, Alabama; Baton Rouge, Louisiana; and Jackson, Mississippi, forecasters said.

NWS meteorologist Mike Edmonston said: “We’ll see all three threats as far as hail, wind and tornadoes on Tuesday.”

The storms have been responsible for three deaths this week and, as of Tuesday evening, more than 350,000 customers were without power from Texas to Maryland, including 143,000 in Mississippi and 76,000 in Virginia, according to poweroutage.us.

Alabama Power Co reported some 93,000 homes and businesses without electricity statewide.

With warnings about possible tornadoes stretching from Louisiana eastward, dozens of school systems in Mississippi and Alabama dismissed students early so buses and cars would not have to be on the road during potentially violent weather.

Severe Weather-Mississippi
Alfred Lee, of Tupelo, Mississippi cleans up debris after a tornado hit the area (Adam Robison/The Northeast Mississippi Daily Journal via AP)

A Tennessee woman died when a tree fell on her home as storms moved through the state on Tuesday, Weakley County Emergency Management director Ray Wiggington told WKRN-TV. He said at least six mobile homes were damaged by the falling tree around 4am.

At least eight people were injured when storms that brought tornadoes to Texas flipped tractor-trailers on an interstate and damaged structures.

Three drivers were hospitalised, one with serious injuries, after their tractor-trailers overturned in the storms on Monday night along Interstate 35 near Waxahachie, about 30 miles south of Dallas, officials said.

In addition to the injured tractor-trailer drivers, five others in Texas were hospitalised after the storm came through Ellis County, an official said.

County Judge Todd Little told KXAS between 25 to 50 structures were damaged, but they had no fatalities.

NWS meteorologist Faith Borden said at least 11 Tennessee counties were hit by possible EF-0 tornadoes Tuesday.

The Tennessee Emergency Management Agency said one weather-related death was reported in Weakley County, but spokesman Dean Flener did not have details about the manner of death or exactly when it occurred.

Severe Weather-Southern Plains
Twelve tornadoes hit Mississippi on Sunday night (Yffy Yossifor/Star-Telegram via AP)

Strong winds and heavy rain whipped through Mississippi’s capital city of Jackson late on Tuesday while thunder rattled windows.

The high winds knocked out electricity in many neighbourhoods while it cracked some limbs off trees and sent them onto nearby houses. The storms left streets littered with branches and leaves.

On Monday, a falling tree brought power lines onto his vehicle in Douglasville, Georgia, west of Atlanta, Douglas County spokesman Rick Martin said.

And in middle Georgia, Carla Harris, 55, was killed after a tree fell onto her Bonaire home, Houston County emergency officials said.

A tornado that struck Virginia’s Northumberland County near the Chesapeake Bay destroyed one home and severely damaged a few others on Monday, but no one was injured.

The tornado tracked for about five miles and carried winds of up to 120 mph.

In Mississippi, forecasters confirmed 12 tornadoes on Sunday night, while tornadoes touched down in South Carolina and southern Kentucky on Monday.