HOUSTON (Reuters) - Torrential rainfall totaling 18 inches pummeled Houston on Monday, causing floods that were believed responsible for five deaths and that snarled transport and turned roads into lakes in the fourth most-populous U.S. city.
More than 1,000 homes were flooded in Harris County, which contains Houston, and there were more than 1,000 water rescues as scores of neighborhoods and roads were hit by rushing water.
"This is the most I have ever seen in the state of Texas," Governor Greg Abbott said of the rescues at a news conference, where he declared a state of disaster in nine Texas counties. He warned that flooding risks would remain for several days.
Abbott also said U.S. Internal Revenue Service officials allowed extensions for taxpayers in flooded areas who missed filing deadlines on Monday.
Medical examiners and media reports said five bodies were found and that officials were working to see if those people died because of the high water.
Dozens of horses were rescued from a flooded stable near Cypress Creek. Television stations filmed some of the animals struggling in neck-high currents before Harris County deputies reached them by boat.
Ed Emmett, the top political official for Harris County, signed a disaster declaration for the county. He told a news conference that 13 creeks and water channels designed for drainage had overflowed, causing floods that blocked roads.
Floods also hit highways running through Houston, including Interstate 10, a major U.S. east-west corridor.
Houston Mayor Sylvester Turner canceled his State of the City speech planned for Monday, instructing all non-essential city employees to stay home.
"This not the day to be on the roads in the city of Houston," he said.
The city temporarily turned one shopping mall into an evacuation center.
More than 40,000 customers were without power in the Houston area because of the severe weather, CenterPoint Energy reported.
As of 5 p.m. CDT (2200 GMT), more than 1,200 flights at major airports in Texas were canceled, according to FlightAware.com.
No significant impact was reported for oil fields and the belt of refineries around Galveston Bay.
Energy industry intelligence service Genscape said a gasoline-producing unit was taken out of production at Royal Dutch Shell Plc's joint-venture Deer Park refinery. It was unclear if weather was a factor in the unit's shutdown.
The rains were expected to cause rivers to crest later in the week, bringing floods to downstream areas, the weather service said.
(Writing by Jon Herskovitz; Additional reporting by Terry Wade and Erwin Seba in Houston and Jim Forsyth in San Antonio; Editing by Bernard Orr and Peter Cooney)