4:10 P.M. UPDATE:
Two separate fires in Northwest Arkansas that began midday Sunday had coalesced into one by Monday afternoon, the National Park Service said.
The fires, which were previously said to cover 65 acres, continued to burn within a containment zone firefighters worked to reinforce. The zone is located along Arkansas 21 on the north side of Boxley Valley near the Buffalo National River, a combination of private and national park lands.
Much of that area is on or near vertical hillsides in rough terrain, the agency said.
The fire is still burning but staying contained despite high winds and dry fuel, according to the release. There were no reports of injury or property damage, and the causes of both fires remain under investigation.
The National Park Service will estimate the acreage burned Tuesday.
Read Tuesday's Arkansas Democrat-Gazette for full details.
Two fires covering 65 acres in Northwest Arkansas remained only 10 percent contained Monday, the National Park Service said.
In a news release, the department said multiple fire departments responded after reports of two separate fires along Arkansas 21, near the Buffalo National River, on Sunday. The crews remained with the fires until 8 p.m., when they were reportedly called back for their own safety.
On Monday, the National Weather Service issued a red flag warning, citing windy, dry conditions that could increase the risk of wildfires. The warning is in effect through 6 p.m.
Unseasonably warm temperatures are also expected, The Associated Press reported, with temperatures reaching the low 70s in some areas.
The National Park Service said the fires in northwest Arkansas are expected to grow Monday. Their cause is still under investigation.
The Associated Press contributed to this story.