At least three people are dead and 12 reported missing after massive flash flooding in parts of Texas over the weekend. (Reuters)

Days of flash flooding, tornadoes and historic rainfall across central Texas and Oklahoma swept away hundreds of homes and left at least five people dead and a dozen missing, emergency officials said Monday.

Rescuers in helicopters and pontoon boats rushed to save stranded residents across the southern Plains states over the Memorial Day weekend, as severe storms led fast-rising waters to overflow rivers and roads during flooding that the National Weather Service called “catastrophic.”

More than 1,000 people were evacuated and at least five were killed during hours of vicious winds and drenching storms, including a 14-year-old Texan whose body was found Monday in a deluged storm drain, officials said.

A longtime Oklahoma firefighter was swept away and killed Saturday night in Claremore, a small town outside of Tulsa, while helping save trapped families gathered for a girl’s fifth birthday party, TV affiliate FOX 23 reported.

Texas Gov. Greg Abbott (R) declared a state of emergency in 24 counties on May 25, after parts of the state were pounded by flash flooding, tornadoes and heavy rainfall over Memorial Day weekend. (Reuters)

A high school senior in Devine, Tex., died amid violently surging floodwaters while driving home from her prom Saturday night, police said.

An unidentified man’s body was recovered in San Marcos, Tex., along a flooded bank of the Blanco River. A 33-year-old Tulsa woman was also killed in a traffic accident Saturday evening after the car she was driving was rammed by a hydroplaning truck, police said.

In Mexico, a tornado that tore through the border city of Ciudad Acuña on Monday decimated a seven-block swath and killed at least 13 people, including three infants, authorities said. Hundreds of homes were damaged or destroyed, and more than 200 people were rushed to hospitals.

Twelve people, including three children younger than 10, were said to be missing Monday after two families took shelter at a house that was destroyed in the small town of Wimberley, Tex., where officials said more than 350 homes have been washed away.

The town, on the bank of the Blanco River between Austin and San Antonio, was one of the hardest hit in the weekend floods. The river swelled more than 30 feet there within three hours Sunday, scattering wet wreckage and overrunning nearby Interstate 35.

Torrential rainfall hurt search efforts, washing away police cars and flooding a fire station in San Marcos. The Oklahoma City Fire Department said it had rescued more than 70 people amid pummeling storms.

Areas of Texas saw massive storm damage from flooding over Memorial Day weekend. (Sarah Parnass/The Washington Post)

Texas Gov. Greg Abbott (R) on Monday added 24 counties — including Hays — to the 13 that were declared states of disaster this month, allowing them to tap extra resources to aid with the crisis.

Officials instituted a curfew Monday for the second night in a row, warning residents to stay away from rubble-strewn areas.

Tornadoes and heavy winds Sunday battered buildings in Texas and along the Mexico border, including at a ravaged Houston apartment complex at which two people were hurt. Emergency officials in Texas estimated the area had suffered millions of dollars in damage.

Dallas faced severe floods from the Trinity River, which joined the Red and Wichita rivers in rising far above its normal level. The city saw more than three inches of rain Sunday, making it the wettest May 24 in more than a century.

The rain has added to the wettest May on record for cities in several southern Plains states. Oklahoma City, which received four inches of rain last year, has recorded more than 27 inches this year.

The rain brought an end to Texas’s extreme droughts, and officials said Monday they were bracing for another round of battering storms and several inches of rain.

“It’s not over,” Hays County Judge Bert Cobb told a news conference Monday. “The rain is still here.”