Heavy downpours in South Texas washed out roads and left motorists stranded Tuesday as forecasters warned that a threat of more severe weather could cause dangerous flooding in already inundated counties near the Mexican border.

The storms dumped up to a foot of rain in some rural areas of Texas, prompting dozens of flood rescues across the region and officials closing parts of a busy highway for hours near Uvalde, about 80 miles (129 kilometers) west of San Antonio. A flood watch also included Kerr County, where last year’s catastrophic flooding along the Guadalupe River killed more than 100 people.

No deaths or injuries were immediately reported Tuesday.

The National Weather Service warned that overnight storms could dump more than a foot of additional rain in some locations through Wednesday, creating potentially catastrophic impacts from flash flooding in areas west of San Antonio. Texas Governor Greg Abbott issued a disaster declaration for dozens of counties.

“Intense rainfall rates and the compounding effects of multiple rounds of storms will result in a dangerous flash flooding threat through Thursday,” the National Weather Service said.

On Tuesday, authorities released videos of rescuers in boats through flooded streets and a vehicle swept downstream by fast-moving waters. Five people were rescued by members of the Texas Game Warden Search and Rescue Team and four were rescued by a local game warden, said Maggie Berger, spokeswoman for the Texas Parks and Wildlife Department.

In Uvalde, authorities said at least two dozen water rescues had been carried out. They opened a local events center for anyone displaced by the floods.