OKLAHOMA CITY -- Residents of the southern Plains cleaned up Thursday after a night of storms that spawned 51 tornadoes, assessing the damage and flooding under sunny skies but with the threat of even worse storms on the horizon.

The storms strafed northern Texas, Nebraska and Kansas on Wednesday and early Thursday but reserved their worst for the Oklahoma City area, where at least a dozen people were injured in a trailer park, and a 42-year-old woman was killed.

The woman, whose name wasn't released, apparently took cover in an underground storm shelter and then drowned when it was deluged by floodwater, police Sgt. Gary Knight said.

While residents assessed the damage early Thursday afternoon, a large cluster of thunderstorms developing in western Oklahoma was expected to bring hail and damaging winds to the state.

Meanwhile, the conditions appeared to be ripe for storms that could produce more powerful tornadoes in the Plains today and Saturday, said meteorologist John Hart of the Storm Prediction Center in Norman, Oklahoma.

"The conditions are right; it's the right time of year," Hart said.

"There are just a lot of things that make you think over the next three days there will probably be big tornadoes across the southern Plains."

An area covering southern Kansas, western Oklahoma and parts of North Texas likely would bear the brunt of the storms Friday and Saturday.

The likelihood of another round of storms so soon left some residents wondering whether they should wait to begin cleaning up.

Oklahoma Gov. Mary Fallin declared a state of emergency for 12 central Oklahoma counties.

The hardest-hit appeared to be the rural community of Bridge Creek, about 30 miles southwest of Oklahoma City, where 25 homes were destroyed.

Flooding remained a concern throughout the region after 5 to 8 inches of rain fell in many areas, said Forrest Mitchell, a meteorologist with the National Weather Service in Norman.

The 7.1 inches that fell at the Oklahoma City airport easily eclipsed the previous daily high of 2.6 inches, he said.

Heavy damage also was reported in Norman and Oklahoma City.

A hotel and mobile home park along Interstate 35 in south Oklahoma City were damaged heavily by a rain-wrapped tornado that dropped from the sky after dark.

Oklahoma City spokeswoman Kristy Yager said crews still were conducting preliminary damage assessments, but they were more worried about ominous storms heading toward the state.

"We're concerned about the weather that's coming in," she said. "About receiving more rain tonight, Friday and Saturday. It's important that everybody stay weather aware and have a plan."