By Jon Herskovitz and Jim Forsyth
AUSTIN, Texas (Reuters) - Rescue workers searched on Tuesday for 12 people missing in Texas after torrential rains slammed the state and Oklahoma during the Memorial Day weekend, killing six people and causing floods and tornadoes that destroyed homes and swept away bridges.
More bad weather was expected with the National Weather Service issuing a flash flood warning on Tuesday morning for Houston, the nation's fourth most-populous city, as a line of thunderstorms moved along the Gulf of Mexico coast from Texas toward Florida.
Four people were killed in Texas on Monday and two in Oklahoma, where thunderstorms and tornadoes slammed several parts of the state.
Rescue workers looked for 12 members of two families missing after their vacation home was swept off its foundation in Wimberley, a town about 30 miles southwest of Austin, where flood waters caused a wave of destruction.
"It's a tremendous clean up operation," said Wimberley Mayor Steve Thurber. "(People) have lost their homes, they have lost their livelihoods in some businesses."
About 100,000 customers were without power on Tuesday morning due to high winds and rising waters that toppled trees and caused power poles to snap.
In Houston, some school districts closed for the day and municipal courts suspended cases for Tuesday morning due to the storms that drenched the area, leaving thousands to wait out the rains on Monday night in places such as the Toyota Center arena where the Houston Rockets had a NBA playoff game.
"I don't think it's smart for anybody to try to be out on this weather," Rockets center Dwight Howard, who was among those waiting out the storm with fans, was quoted as saying by the Houston Chronicle.
Rainfall tallied as much as 7 inches on Monday in parts of Austin, where emergency crews in boats and helicopters rescued stranded residents who could not escape flooding.
Texas Governor Greg Abbott has declared numerous counties disaster areas.
(Reporting by Jon Herskovitz in Austin and Jim Forsyth in San Antonio; Additional reporting by Suzannah Gonzales in Chicago and Scott DiSavino in New York)