A crippling winter storm lashed the central United States with another blast of freezing rain, sleet and snow, causing widespread power outages and tying up highways and airports.

The storm was expected to continue through the weekend, laying down a coat of ice and snow from Texas to Illinois, where an ice storm warning was in effect through Monday morning.

"We're in the middle of this storm," said Joe Pedigo, meteorologist for the National Weather Service in St. Louis. "Friday was the first of three waves."

Farther west, frigid arctic air reached as far south as southern and central California, where plunging temperatures prompted worry about the homeless and crops.

The storm in the Midwest had been blamed for at least seven deaths, and brought passenger train service in Missouri to a halt on Saturday. Trees and other debris knocked down by the weight of ice blocked tracks at several locations between St. Louis and Kansas City.

About 115,000 homes and businesses had no electricity Saturday in the St. Louis area. Between 60,000 and 70,000 customers were without power in Springfield, Missouri, according to a county official.

Missouri Governor Matt Blunt declared a state of emergency Saturday and activated the National Guard. He said the worst wave may come Sunday.

More than 6 inches (15 centimeters) of rain fell in places across central Texas, causing local flooding. Water also blocked three highways in southeastern Oklahoma, the Department of Transportation reported.

About 300 flights were canceled Saturday at Dallas-Fort Worth International Airport, spokesman David Magana said. Cancellations also were reported in St. Louis, Kansas City, Oklahoma City and Tulsa.

In Oklahoma, about 40,000 customers were without power early Saturday, said Michelann Ooten, spokeswoman for the Oklahoma Department of Emergency Management.

More rain, freezing rain and snow was expected from northwest Oklahoma all the way to Wisconsin on Sunday, Pedigo said.

In California's San Joaquin Valley, where much of the state's nearly $1 billion (euro780 million) citrus crop is grown, temperatures dropped into the teens overnight Friday. Growers burned fires, sprayed warm irrigation water and ran giant fans to keep cold air away from their oranges, lemons and tangerines.