By Steve Olafson
OKLAHOMA CITY (Reuters) - A wildfire burned for a third day in a wooded 18-square-mile area of Oklahoma's capital on Thursday and has consumed at least 25 homes, including rambling mansions with horse facilities.
But fire officials said they were confident the blaze won't spread further, even as other parts of Oklahoma continued to be plagued by wildfires including a fierce conflagration in Cleveland County that threatened to reach Norman.
Meanwhile in neighboring Texas, lighter winds and slightly lower temperatures aided firefighters' efforts to contain a raging wildfire near a lakefront resort outside Fort Worth.
In the Oklahoma City fire, firefighters were relying on water trucked in by vehicles or dropped from the sky by two National Guard helicopters after the blaze spread beyond the reach of city water lines.
The closest available city fire hydrant was miles from where the fire advanced as southerly winds pushed it northward, said Marc Woodard, an assistant fire chief for the city.
Oklahoma City encompasses 660 square miles and does not provide water service to some of its farther reaches, where residents rely on wells.
But with electricity knocked out by fire, many homeowners said they couldn't pump water to protect their homes.
Firefighting task forces from 25 counties helped fight the fire, and bulldozers from the state's forestry services agency were delivered on Thursday as Oklahoma Governor Mary Fallin arrived to offer encouragement and thanks.
"Hopefully we'll get some relief on Sunday," she said, referring to forecasts of milder weather across the region.
They're hoping for the same in drought-hit Texas, where the Texas Forest Service reported 16 active large fires on Thursday. Both states have experienced record heat this summer and devastating drought.
"August has been scary hot," said John Nielson-Gammon, a professor in the Department of Atmospheric Sciences at Texas A&M University, adding that the summer of 2011 would be a summer "Texans will tell their grandchildren about" with records broken in June, July and August.
A Texas wildfire burning on the shores of Possum Kingdom Lake, a popular recreation spot about 75 miles west of Fort Worth, was 50 percent contained after charring 6,500 acres of land and destroying 40 homes.
"We have a very aggressive effort going to contain this fire," Texas Forest Service spokesman John Nichols said of the blaze, which broke out on Tuesday and was the largest of the state's active fires.
Texas Governor Rick Perry renewed the state's disaster proclamation on Thursday and urged caution over the holiday week. All but three state counties are under a burn ban.
"In the midst of one of the worst wildfire seasons in our state's history, all it takes is a single, unnoticed spark to cause a disaster," Perry said.
Officials evacuated several Possum Kingdom neighborhoods along the lakeshore, with some residents forced to flee by boat because roads were cut off by flames. A few were allowed to return briefly to inspect their property on Thursday.
About 400 firefighters were battling the blaze, using water dropped continuously from single-air tankers, helicopters and other aircraft, Nichols said.
The fire is the second large blaze at this site this year. A two-week fire in April destroyed 160 homes and burned more than 126,000 acres.
The combination of triple-digit heat, low humidity and winds gusting over 20 miles per hour, along with the parched conditions due to a prolonged and historic drought, fed the wildfire outbreak this week, officials said.
Weather conditions this weekend could present a new danger, especially for fires that aren't contained, said Steve Fano, a meteorologist for the National Weather Service in Fort Worth.
"We're looking at a cold front arriving this weekend, which will mean lower temperatures but a lot gustier winds," he said.
The Texas Forest Service has declared this to be the worst fire season in the state's history.
(Additional reporting by Marice Richter in Dallas and Jim Forsyth in San Antonio, Editing by Karen Brooks and Cynthia Johnston)