OKLAHOMA CITY - The ice storms that have been blamed for at least 21 deaths continued to lash much of the nation Sunday, as crews tried to restore power to hundreds of thousands and slick roads spawned accidents.
Waves of freezing rain, sleet and snow since Friday have caused at least 12 deaths in Oklahoma, six in Missouri, two in Texas and one in New York.
Seven adults were killed early Sunday near Elk City, Okla., when the minivan they were in hit a slick spot on Interstate 40, crossed the median and hit a tractor-trailer, the Oklahoma Highway Patrol reported.
Missouri Gov. Matt Blunt said about 300,000 households there remained without power on Sunday. About 350 National Guardsmen were going door to door checking on residents in the hardest-hit areas and were helping to clear slick roads of tree limbs and power lines.
"We have what appears to be a three-wave storm," he said. "We're in the final wave of it."
About 122,000 customers lacked power in Oklahoma, the state Department of Emergency Management said. A gymnasium roof collapsed in Del City, Okla., under the weight of ice and snow, but no one was inside or injured, authorities said.
In Texas, 415 flights were canceled Sunday at Dallas-Fort Worth International Airport.
In Nebraska, which has been pummeled by winter storms in the past month, the weekend storm dropped even more snow, making roads treacherous.
As the storm began to fade from the nation's midsection, parts of the East began to suffer.
In Albany, N.Y., a 22-year-old died after falling about 90 feet from a bridge to a road below after climbing a railing to avoid being hit by a sliding car. He had gotten out of his vehicle around 2 a.m. after a crash.
In Syracuse, N.Y., Interstate 81 was closed for about two hours after about 30 cars were involved in six accidents early Sunday. Several people were taken to hospitals.
The storm system was expected to continue heading northeast, said National Weather Service meteorologist Joe Pedigo. While the Ohio region could see rain Monday afternoon, lower Michigan and parts of New England could see more than a foot of snow.
In the St. Louis region, about 150,000 people remained without power Sunday afternoon, after a pattern of freezing and thaws.
"We've had three real pushes of rainfall," said National Weather Service meteorologist Jim Kramper.
One was Friday, one Saturday and a third came Sunday afternoon and persisted into the evening.
Anthony Younger, 29, on a break from his job as a fast-food restaurant manager, said his family has lost power three times in stormy weather since this summer, once for about two weeks, he said.
"Here we go again," he said when his power went out in the St. Louis suburb of Florissant this weekend. It has since been restored.
Severe storms in July led to a power blackout of several days in the St. Louis area.
Younger said relatives now are in the habit of checking in with one another, figuring out who still has electricity and shuttling between residences.
Despite his experience, weather-related disruptions don't get easier, he said. "You never get used to it."