Rescuers aboard boats and helicopters have saved more than 200 people, including stranded drivers and people trapped in homes, Abbott said.
The governor said the hardest-hit areas are expecting more rain into Friday and are not out of danger yet, with some rivers expected to reach historic levels.
After days of pounding rain, the National Weather Service said a large wave on Thursday barreled down the same river wrecked by flash floods last summer when two dozen children and counselors died at Camp Mystic.
Much like last year, the floods came in the middle of the night. But this time some residents in the Texas Hill Country said they received more warnings.
Forecasters urgently warned, “Move to higher ground now!” as rivers rose hour by hour. Some spots of the Guadalupe River rose by more than 30 feet (9 meters).
The governor said more than 2,000 first responders had been deployed and some evacuations began before the worst of the flooding.
“What happened last year was a warning to people on or near rivers," Abbott said. “No one can be complacent.”
As much as 28 inches (74 centimeters) of rain fell over the past three days in Uvalde County, which was spared from the worst flooding a year ago, the weather service said Thursday. Other areas saw roughly a foot of rain.
Victims in Texas floods were swept away
The governor said one of the victims was driving on a flooded road and was swept away near Uvalde while the other died in Kerr County.
Jennie Steward said the body of her husband, 65-year-old John Mark Steward, of Kerrville, was found Thursday.
She was visiting her parents when a neighbor called overnight, saying her husband was missing after water had risen to the door of their mobile home, which stood off the ground.
The entire home was swept off the platform and floated down Goat Creek on the Guadalupe, she said.
“It’s really hard that I wasn’t there with him,” she said. The two last spoke by phone Wednesday to celebrate their third anniversary.
