A brush fire burning near the Pacific Crest Trail was holding at 719 acres Friday and was 15-percent contained, according to Cal Fire.
The "Cowboy Fire" was reported at 1:13 p.m. Thursday, burning between the communities of Campo and Potrero.
"Firefighters worked throughout the night in extremely steep terrain and heavy fuel (brush), which hasn’t burned in over 100 years," said California Department of Forestry and Fire Protection spokesperson Roxanne Provaznik. "As expected the fire activity has increased slightly, but there are no homes currently threatened."
No roads are closed and no homes have been damaged.
The blaze sent a towering column of smoke into the air by Thursday afternoon.
“The smoke is highly visible from the backcountry,” said Provaznik.
Provaznik said at about 4:30 p.m. Thursday that the fire was approaching Star Ranch and that a strike team of engines would stage there for structure protection. Two hours later, though, authorities said the fire was considered to be a "minimal threat to structures" and that the blaze was back-burning on itself.
Officials said at 8:45 p.m. that the fire had burned 719 acres and that crews were beginning to get a handle on the blaze -- in fact, Cal Fire estimated it was 10 percent contained at that point. Authorities said firefighters would continue to battle the fire through the night.
Campo Elementary School's 425 students were evacuated as a precaution around 1:45 p.m. because the fire was “getting pretty close,” according to a Mountain Empire School District spokesperson. The students were taken to Mountain Empire High School.
The cause of the fire is under investigation.
Campo is about 50 miles east of San Diego near the U.S.-Mexico border.