Houston submerged as wild weather kills 20 in US, Mexico

More than 10 inches (25 centimeters) of heavy rain fell in just a few hours, triggering the worst flooding in at least a decade

Torrential rain left large parts of Houston submerged today and trapped fans at an NBA basketball game, in savage weather that has killed nearly 20 people in the United States and Mexico.

The southern US states of Texas and Oklahoma, and far northern Mexico, have borne the brunt of several days of wild weather, including tornadoes, which have left scores dead, missing and injured on both sides of the border.

More than 10 inches (25 centimeters) of heavy rain fell in just a few hours in the Texas city of Houston, triggering the worst flooding there in at least a decade and stranding at an arena spectators who had gone to watch a Houston Rockets basketball game last night.

Images from a local CBS affiliate in Houston showed hundreds of abandoned cars entirely under water on roadways and flooded streets abandoned. Some people were trapped in their cars, others marooned in their homes.

Two people died overnight in the flooding in the city, Mayor Annise Parker said, with the toll expected to rise.

"I want to ask and urge people to continue to be safe and recognize that we may have more rain later today," she said, encouraging people to stay at home in America's fourth-largest city by population.

"We have cars littered all over the city," she told a press conference, adding that emergency crews were attempting to reach the abandoned vehicles to see if anyone had been trapped inside.

Downtown Houston, where the Toyota Center arena is located, was not under water, said Parker, but about 200 fans had been unable to get home from the NBA game for several hours after the deluge.

Fears were growing meanwhile for at least 12 people still missing in Hays County, also in Texas, officials said.

One person was already confirmed dead there and two more died in Oklahoma, which is located to the north of Texas.

Many of the dozen missing in Hays County were from one house that was torn from its foundations during a flash flood at the weekend.

There were two families staying at the A-frame house in the picturesque town of Wimberley for the long Memorial Day weekend, NBC News reported. Among them were three children.

Inside was Laura McComb, who was on the phone with her sister when the house, built on stilts, broke off and was swept away.

"We are in a house that is now floating down the river," she reportedly told her sister, Julie Shields. "Call Mom and Dad. I love you. And pray.