(CNN) -- Strong winds whipped up wildfires in central, south and west Texas Friday, complicating efforts to bring various blazes there under control.
Texas Forest Service spokesman Bruce Palmer said the group's crews are battling at least 10 major fires, which have so far scorched more than half a million acres.
Winds were starting to pick up, he said, adding that about two-thirds of Texas is under a "red flag" warning, meaning that critical fire weather conditions are either occurring now or will occur shortly.
The National Weather Service issued red-flag warnings for much of central, south and west Texas, citing strong winds and relatively low humidity. It said gusts of up to 60 mph were possible in some places.
"It's just going to make things a lot more difficult," said Palmer. "It's extremely dangerous conditions."
The largest of those 10 fires is the so-called Rockhouse fire in west Texas. It has so far burned nearly 300,000 acres and is about 66 percent contained, according to forest service officials.
They said 212 of the state's 254 counties are reporting burn bans.
South of San Angelo, in central Texas, authorities have ordered the evacuation of 75 homes, according to Lt. Christina Lopez with the Tom Green County Sheriff's office. The city is not in danger and the evacuation order was precautionary, she said.
Authorities have responded to 7,807 fires across more than 1.5 million acres since this year's wildfire season began in late December, Gov. Rick Perry wrote earlier this month in a letter to President Barack Obama. Perry requested that the federal government declare Texas a disaster area. Fires have affected all but two of the state's 254 counties.