SPARTANBURG, S.C. » Drenching rains along an already-saturated East Coast caused major flooding Thursday, drowning a woman whose car quickly filled up with water and prompting flash-flood warnings from historic Charleston to Washington, D.C.

An early-morning downpour dumped 4 inches of rain on Spartanburg in a short time, causing floods that submerged several cars. To the northeast, one person died and another was injured in a crash near Fayetteville, North Carolina, when a tree fell across an interstate and hit two cars.

Residents across the region were bracing for several more days of rain and a possible strike by Hurricane Joaquin — a major Category 4 storm set to wallop the Bahamas and move toward the U.S. Joaquin could intensify damage around the region, but more rain is forecast regardless of the storm’s path.

In South Carolina, 56-year-old Sylvia Arteaga was driving home after a night shift at Grace Management Group on Thursday morning when authorities said the floodwaters trapped her underneath a railroad bridge at the edge of Spartanburg. Below the bridge, the street narrows to one lane and cars have to alternate passing under it to let traffic flow through.

Spartanburg County Coroner Rusty Clevenger said in a news release Thursday that Arteaga’s car flooded "to capacity" inside.

Hattie Palafox, a middle-school teacher and family friend, described Arteaga as a "very sweet, very kind, very loving" mother of 17- and 20-year-old daughters. Palafox said she had discussed the weather forecast with Arteaga earlier this week, but she hadn’t seemed concerned about the expected heavy rains.

"She was very, very soft-spoken. I couldn’t say enough about her," Palafox said after placing a bouquet of flowers at Arteaga’s home, not far from where she died.

Palafox said she made it a point to keep up with Arteaga and her two daughters after her husband died of a heart attack two years ago.

The house is located on a narrow, quiet street not far from a highway and bordered on one side by a mobile home park. Relatives of Arteaga declined to comment.

Elsewhere in Spartanburg County, authorities said a man was rescued Thursday morning after his vehicle was swept off the road where a culvert had washed out. The man managed to cling to a tree and was taken to a hospital for treatment.

Authorities around the region have warned of saturated soil giving way to falling trees, which appears to have played a role in the death near Fayetteville.

In the historic city of Charleston, National Weather Service urged motorists to avoid driving in downtown Charleston unless absolutely necessary. Forecasters said a storm that moved through early Thursday afternoon dumped at least 2 inches of rain on the city and the Weather Service posted a flash-flood warning for areas of the city through early evening.

The Weather Service said that streets were expected to flood and with high tides, the water would be slow in receding from roadways.

South Carolina Gov. Nikki Haley declared a state of emergency Thursday night, allowing government agencies to immediately start making preparations.

North Carolina Highway Patrol Lt. Jeff Gordon said the fatal crash happened on Interstate 95 about 1:30 p.m. when a tree fell across the road, hitting two vehicles.

Gordon says the passenger in one of the vehicles died, and the driver was taken to the hospital. There was no immediate word on the survivor’s condition, and the driver of the second vehicle was not hurt.

Gordon said the area has had a lot of rain in the past several days. The National Weather Service reported light rain and winds of about 10 mph around the time of the wreck.

Governors up and down the coast warned residents to prepare for more heavy rains. In addition to South Carolina, states of emergency were declared in Maryland, New Jersey, North Carolina, and Virginia.

The National Weather Service issued flash-flood watches for Washington, D.C., northern Virginia, southern Maryland and the Eastern Shore from Friday morning through late Saturday.

Associated Press Writer Meg Kinnard in Columbia, South Carolina, contributed to this report.