Story highlights 30 people reported injured in the storms

Some flood warnings will remain in effect into the weekend

50 reports of tornadoes

(CNN) Oklahoma declared a state of emergency in a dozen counties Thursday as the state and several others recovered from severe storms.

Heavy winds and dangerous amounts of rain have pounded Kansas, Nebraska, and Texas as well. The rain continued to fall Thursday, pushing some rivers and creeks up to or over their banks.

The storms and flooding "have caused extensive damage to public and private properties," Oklahoma Gov. Mary Fallin said in issuing an emergency declaration for 12 counties. The weather "threatens the lives and property of the people of this state and the public's peace, health and safety."

The counties are Alfalfa, Blaine, Caddo, Canadian, Cleveland, Dewey, Garfield, Grady, Grant, Major, McClain and Oklahoma. At least 30 people were reported injured in the storms, the state Department of Health said.

The good news: A second day of tornadoes appears unlikely, with the National Weather Service Storm Prediction Center forecasting only a slight chance of powerful thunderstorms in the Great Plains and parts of Texas, including the Dallas area.

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