A fire that started along Interstate 40 in Roane County snaked its way up Rockwood Mountain on Monday night.

Nathan Waters, assistant district forester with the Tennessee Division of Forestry Administration, said the fire encompassed 10-15 acres and had worked its way below Airport Road.

No homes were threatened. The terrain is steep, rocky and wooded.

Drivers will know the area because of the steep grade they face as they head up the interstate toward the Plateau. It's near the Central Time Zone border.

Waters said it's likely the fire started from something such as sparks from truck brakes or tossed debris. He said he doubted anyone deliberately set it because of the busy and treacherous location where it broke out.

He described the fire as resembling a finger, long and narrow.

Firefighters cut "the head" off of it and were addressing its flanks, where fire still was active, according to Waters. Authorities may let the lower end of it burn out on its own, he said.

By 9 p.m. the blaze had been burning for several hours.

Waters said firefighters likely would not stay on site trying to fight it overnight because the ground is so rough and steep and because it's so dark.

"They want to be able to see what they're doing," he said.

He was confident, however, the fire would not be allowed to burn if it posed a danger to anyone.