Wind-driven grass fires that destroyed at least two dozen homes and forced hundreds of evacuations continued to burn Friday in southern Oklahoma, which remained extremely dry despite snowfall earlier in the week.

The worst fires raged in Carter County near Ratliff City, after burning through at least 20 homes overnight, and west of Marlow in Stephens County, said Michelle Finch, fire information officer for the Oklahoma Forestry Department.

Four heavy air tankers dropped retardant on the Carter County fire until dark Thursday and resumed doing so at first light Friday. The fire, which was four miles wide, had burned an estimated 7,000 to 10,000 acres and was about 50 percent contained by 9 a.m CST, said Richard Reuse, an information officer for the state's fire response center.

As many as 18,406 acres burned statewide on Thursday and at least 11 fires were reported, said Cliff Eppler, an information officer for the state's fire response center. There were no reports of injuries, officials said.

In a group of Carter County towns about an hour's drive south of Oklahoma City, authorities evacuated more than 800 homes in Tatums, Fox, Clemscott and Graham, sending residents who needed shelters to gymnasiums in neighboring towns, officials said. Windy conditions were contributing to the spread of the fires, and shifting winds increased the danger.

"When that front went through here it was unbelievable," Reuse said. "Flags just whipped around their directions and the fire went roaring the other way. That's to be expected when a cold front comes through. It's a real dangerous situation."

Another major fire still burned Friday morning in northwest Stephens County, near Central High School. That fire has burned an estimated 10,000 acres, Reuse said, and destroyed at least four homes.

Another fire in Carter County, near the town of Springer, burned 1,000 acres but had been contained, he said. It did not damage any homes.

"A small fire can get up to 1,000 acres in half an hour with these weather conditions," he said.

Gov. Brad Henry had planned an aerial tour of fire-damaged areas in southern Oklahoma on Friday, but canceled the trip so that the helicopter can be used to fight the fires, said his spokesman, Paul Sund.

There is little if any chance of precipitation in the seven-day forecast, according to National Weather Service meteorologist John Pike. He said the fire danger will remain high through at least Tuesday.

"We're supposed to be in winter, but it doesn't look like any winter weather is coming," Pike said.

In Oklahoma alone, grass fires have burned more than 401,000 acres, destroyed more than 220 homes and businesses and killed two people since Nov. 1. Wildfires have also menaced Arkansas, Colorado, New Mexico and Texas.

In northern Texas, firefighters were battling a blaze that had consumed at least 4,000 acres and was threatening eight homes about 100 miles west of Dallas, the Texas Forest Service said.