By Jon Herskovitz and Jim Forsyth

AUSTIN, Texas/SAN ANTONIO (Reuters) – A U.S. Army truck overturned in a swollen Fort Hood creek on Thursday, killing five soldiers and leaving four missing as storms dumped more rain on flood-hit parts of Texas.

The rising floodwaters in Texas scrambled transportation, further swelled rivers already over their banks and sent more people to evacuation shelters.

The U.S. Army said the truck overturned at Fort Hood’s Owl Creek low-water crossing during a training exercise. Three bodies were recovered downstream, the Army said. It is unclear where the bodies of the additional two soldiers were found.

A search was being conducted for four soldiers from the 1st Cavalry Division, it said in a statement.

Three soldiers were rescued from the water and were in stable condition at a hospital, the statement said. Fort Hood, about 70 miles (110 km) north of Austin, is the biggest active-duty armor post in the United States.

The National Weather Service issued a flash flood warning for parts of east Texas and Louisiana. It placed most of Texas on a flash flood watch because of a slow-moving storm system expected to linger through the weekend.

About 200 flights were canceled in Houston and Dallas as of Thursday evening because of heavy rains, according to tracking service FlightAware.com. Major highways have seen delays caused by accidents linked to the storms, transport officials said.

Texas Governor Greg Abbott declared a state of disaster in 31 counties on Wednesday, mobilizing state resources to help cope with the disaster.

Six people were killed in the past week in Texas due to severe weather.

Thousands of people have evacuated their homes in low-lying areas, rivers have swelled to levels not seen in more than 100 years, and emergency workers have completed hundreds of high-water rescues.

Evacuations were ordered for parts of two towns in Fort Bend County, about 30 miles (50 km) southwest of Houston, where the Brazos River has risen to levels not seen for more than a century.

The pounding rains led to some dramatic rescues, including one in San Antonio of a man described as a Polish immigrant with limited knowledge of English who found himself and his car washed away by a wall of water.

Crews putting up flood barricades heard the man scream and a helicopter was sent to look for him, said James Keith, spokesman for the Bexar County Sheriff’s Department.

“We were able to locate this man standing on the top of a submerged car holding on to a tree,” he said.

(Reporting by Jon Herskovitz in Austin, Texas, Brendan O’Brien in Milwaukee, and Jim Forsyth in San Antonio; Editing by Peter Cooney and Leslie Adler)