Up to 20 inches of rain could fall in parts of South Texas through Thursday evening after slow-moving storms spawned a tornado near Interstate 10 in northwest San Antonio.
Uvalde County has recorded up to 16 inches so far, with officials counting 25 rescues by 9 a.m. Wednesday and warning more people may need help as rivers keep rising.
Flash-flood warnings remained in effect across vulnerable areas west of San Antonio and in Kerr County, where officials contacted summer camps and retreat centers because river flooding could develop quickly.
Greg Abbott issued disaster declarations for dozens of counties as authorities reported no deaths or injuries from the tornado or flooding despite washed-out roads, inundated farmland and vehicles swept by fast water.
Forecasters said tropical moisture from the Gulf of Mexico, reinforced by a stagnant low-pressure pattern, is driving a rare midsummer setup that can bring repeated heavy rain about once every five years.