(Updates with six dead)

OKLAHOMA CITY, Aug 19 (Reuters) - Six people died in floodwaters across Oklahoma after heavy rains from the remains of Tropical Storm Erin drenched the state on Sunday, according to police and local media reports.

Three women from the same family were driving in a van swept away by rushing water, according to the sheriff's office.

The bodies of the three were found after a search of floodwaters near Carnegie, Oklahoma, 93.5 miles (150.5 kilometers) southwest of Oklahoma City, said the Caddo County Sheriff's office.

A woman drowned near Fort Cobb, Oklahoma when she sought shelter in her cellar from thunderstorms, which is the usual procedure for storms in tornado-prone Oklahoma.

"Evidently she went to her cellar due to the storming. She couldn't get the door back open," said Caddo County emergency management director Larry McDuffy.

Another person was confirmed drowned west of Kingfisher, Oklahoma, the Kingfisher County Sheriff's office told the Daily Oklahoman newspaper.

A 67-year-old woman in Seminole, Oklahoma, drowned when her car was swept off a residential street into a flooded drainage ditch by rushing waters, according to the Daily Oklahoman.

As much as 9 inches (23 cm) of rain fell across a wide swath of Oklahoma, leaving roadways under 5 feet (1.5 meters) of water.

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