BOSSIER CITY, La. — Thousands had been evacuated by Thursday morning as a second round of rain hit an already inundated northern Louisiana, where flooding in some places was up to the rooftops and in others submerged cars, stranded families.

Three people drowned in Oklahoma, Texas and Louisiana.

In Bienville Parish, authorities said a man died and a woman was being treated for injuries after their car was swept off a flooded Louisiana road Wednesday and into a creek. In rural southeastern Oklahoma, a 30-year-old man drowned Tuesday night after trying to drive his SUV across a low-crossing bridge covered by floodwater. In Texas, a 22-year-old man drowned Monday night after his canoe capsized in Dickinson Bayou, southeast of Houston near Galveston Bay.

In Bossier City, 3,500 homes were evacuated as a precaution because a bayou was approaching the top of its levee. National Weather Service meteorologist Jason Hansford said Thursday morning that the bayou may top the levee or be breached.

Heavy rain continued across much of north Louisiana on Wednesday night and early Thursday morning with another 3 inches, Hansford said.

State police report several sections of Interstate 20 were closed from Bossier City to near Gibsland in north central Louisiana.

The forecast is for the rain to end by Friday afternoon. Flash flood watches remained in effect for areas from Port O’Connor, Texas, to near Springfield, Illinois.

Air Force Tech Sgt. Drew Scott and another military friend brought in a boat Wednesday to help evacuate up to 200 mobile homes in the Pecan Valley Estates community in Bossier Parish. Scott said he had gone in his truck earlier Wednesday to pick up his in-laws but couldn’t get into the park.

“Water, coming up from the Flat River, was waist deep or higher and going into the houses. There were lots of cars flooded out. At the deepest point, I’d say, it was up to my chest and I’m 6 feet,” he said.

Scott said he and his friend assisted the sheriff’s office, firefighters and others in getting those who were stranded out of harm’s way.

“When things like this happen, people start helping others and that helps restore faith in the country and humanity,” he said. “That’s the way I was raised and the way I raise my family. I would hope that if the shoe was on the other foot and I needed help that someone would do the same for me.”

Sharon Anderson, her three children and four grandchildren were rescued from her south Bossier Parish mobile home after rising water threatened to trap them. Several other families already had been trapped, and the water was still rising, she said.