FORT WORTH, Texas (AP) The threat of wildfires was expected to diminish with climbing humidity levels, but parts of Texas still faced dangerous conditions through the end of the work week, the National Weather Service said.

Fire dangers Wednesday were predicted to be greatest from El Paso to Lubbock, and in north-central Texas.

Roger Erickson of the weather service's Fort Worth office said conditions were still ripe for wildfires but higher humidity "will get us a little bit of relief."

On Tuesday, low humidity trailing a fast-moving cold front created an extreme threat of wildfires. Firefighters in North, Central and West Texas dealt with gusty winds fanning fast-moving wildfires that consumed about 2,000 acres.

Homes were evacuated in Tarrant, Wise, Parker, Burnet, Nolan and Callahan counties. At least two dozen buildings were destroyed.

Two injuries were reported Tuesday, both West Texas firefighters who were involved in a wreck. Some 152 counties more than half in the state were under a burn ban.

In South Texas, firefighters planned to work overnight to contain a 9,000-acre brush fire that broke out in Duval County and spread to Brooks County. There were no reports of injuries, but Hidalgo County Emergency Management Coordinator Tony Pena said at least one trailer had burned, The McAllen Monitor reported.

In Central Texas, a fire that consumed about 1,500 acres in Burnet and Williamson counties was pretty much extinguished by the evening, said Capt. Jim Barho, emergency management coordinator for the Burnet County Sheriff's Department. He said there were no injuries or loss of property.

Two volunteer firefighters were injured when an 18-wheeler driver whose vision was impaired by the smoke rear-ended their vehicle, said David Warren, chief deputy of Nolan County Sheriff's Office.

One firefighter on top of the truck was thrown off, breaking his arm, while the other was taken to the hospital with a head and eye injury, Warren said.

The fires prompted Gov. Rick Perry to active the state's Emergency Operations Center at level one, the highest level, his spokeswoman Allison Castle said.

"We take the threat of wildfires very seriously," she said.

Two CH47 Chinook Helicopters were on standby in Grand Prairie, and six UH60 Blackhawk helicopters were on standby in Austin and San Antonio to deploy as needed. Two of those had been dispatched to Burnet, northwest of Austin.

The Texas Department of Transportation was working with local fire departments to provide fuel for fire trucks.

Some fires were caused by downed power lines as winds in North Texas were reported at more than 50 mph. Power was knocked out for thousands of Dallas customers and strong crosswinds resulted in delays of about 30 minutes for some flights at the Dallas-Fort Worth International Airport. More than 26 outbound flights were canceled.

"It's an issue of safety for us," said airport spokesman David Magana. "When that wind is coming from your left or your right, it presents a danger."

Tuesday's events were similar to the scenario in late 2005 and early 2006, when strong winds, low humidity and dry, high grasses and brush set the stage for massive fires that scorched 2.25 million acres statewide, destroyed more than 730 homes and killed 20 people, including two firefighters.

"It's starting to seem like, 'Here we go again,'" said Texas Forest Service spokeswoman Carrie Smith. "With all the fires we have going today, it is reminding me of what happened in 2005 and 2006."

The National Weather Service said the critical threat was expected to move further south on Thursday to areas including Austin, San Antonio and parts of South Texas.

Friday the threat will be greatest in parts of West Texas.

AP staff writers Angela K. Brown in Fort Worth, Betsy Blaney in Lubbock, April Castro in Austin and Anabelle Garay, Jamie Stengle and Jeff Carlton in Dallas contributed to this report.