HOUSTON - Heavy rain Monday in the San Antonio and Austin areas flooded streets, stranded cars and closed roads.
Rising creeks and streams also threatened some homes, forcing residents to move to higher ground.
San Antonio police reported one death, after a vehicle was swept from a roadway.
In New Braunfels, rescue crews evacuated 24 children from a day care center. Flooding also shut down a large section of the city's downtown.
Gov. Rick Perry authorized use of three Texas National Guard UH-60 helicopters for search and rescue operations. "We hope Texans will take all possible precautions during severe weather to keep them from dangerous situations," he said in a statement.
Tornado warnings were posted in the Houston area as a string of thunderstorms dumped 2-4 inches of rain an hour. The Colorado River, which flows through Austin and into southeast Texas, swelled its banks in several spots.
The Lower Colorado River Authority temporarily closed three of the four open floodgates at Mansfield Dam at Lake Travis after overnight rain. The move was aimed at slowing the rush of water downstream.
The town of El Campo about 72 miles south of Houston, still reeling from weekend flooding that forced 250 people to evacuate, was spared rain Monday.
"The creeks are still up and the town is trying to drain as much as possible," Mayor Randy Collins said. "To my knowledge, the rescue efforts have come to a close and now it's just a big cleanup of a big mess now."
Wharton County had received about 11 inches of rain since Saturday morning, according to the National Weather Service. Parts of U.S. Highway 59 closed after up to 15 inches of rain fell across parts of that county and Jackson County in southeast Texas. The road reopened Monday afternoon.
More rain was possible through tonight.