Hundreds of people have fled areas near Texas rivers that overflowed their banks as the US state reeled from severe storms this week that killed at least 17 people, flooded cities and set a record for the wettest month.
The National Weather Service issued a flash flood watch on Thursday (local time) stretching from south of San Antonio to Dallas, through Oklahoma, where severe weather this week killed an additional six people, and into Kansas. Thunderstorms pelted large parts of the affected region.
The city of Wharton, about 100km southwest of Houston, has issued a voluntary evacuation notice for about 300 homes along the Colorado River, where water was expected to rise throughout Friday.
The Brazos River flooded about 50km west of Fort Worth. Hundreds of people left their homes on Wednesday as the waterway began breaching its banks, Parker County officials said.
State climatologist John Nielsen-Gammon said the average rainfall across the state was 19cm in May, breaking the record of 17cm set in June 2004, according to records that date to 1895. "It has been ridiculous," he said.
The body of a boy was recovered on Wednesday near the central city of San Marcos, Hays County officials said. The boy, who has not been identified, was thought to have been swept away in Blanco River floods that ripped houses off their foundations, county officials said.
There were eight people missing in the county after the flooding, which started on Monday.
The new storms could hinder rescue workers who have been searching for days for those washed away in floods along the Blanco River.
"We are not expecting another surge of the river but it is going to shift debris piles," Kharley Smith, the county's Emergency Management Coordinator, told a news conference.
President Barack Obama has pledged federal support and said the US government has been working with local officials.
Texas has a $US1.4 trillion-a-year economy ($NZ1.95 trillion) and is the country's main domestic source of energy.
Unwelcome visitors
The heavy rains that have pelted Texas and Oklahoma this week brought some unexpected visitors to homes in the region, like 1.22m rat snake that found cover in an unexpected spot at Jeff Lara's residence.
"I opened my grill cover and he jumped at me," said Lara, who lives Edmond, north of Oklahoma City.
Wildlife officials have warned that flooding in Texas and Oklahoma is causing snakes, alligators and other reptiles to seek dry land in populated areas.
They have responded to numerous calls for help, but Lara took matters into his own hands.
"The snake coiled back up, and I took a shovel, scooped him up and tossed him in the yard. He just slithered away."
Non-venomous rat snakes, which can grow up to 1.83m in length and frequent states including Texas, Louisiana, Arkansas and Oklahoma, help keep the rodent population down.
But flooding has displaced the creatures, with removal services such as 911 Wildlife, which has contracts with several Texas cities, receiving reports of more than 1000 of the snakes in North Texas and Houston homes.