A fire smoldering in a remote area north of the Palomar Observatory was holding at almost 170 acres Tuesday, authorities said.
The so-called Cutca Fire erupted for unknown reasons off Palomar Divide Road east of the Cutca Valley in the Cleveland National Forest shortly after 4 p.m. Friday, the U.S. Forest Service said.
The blaze has grown to blacken 167 acres, but fire officials said it didn't spread overnight.
The forest service said the fire was about 75 percent contained, and crews have completed a contingency fireline between Palomar Divide and High Point roads.
No structures have been threatened.
But authorities said about 385 firefighters working to extinguish the blaze still had work to do.
"Heat remains present in the interior of the fire perimeter," according to a forest service statement. "Crews will continue mop-up operations today and the cooler temps expected will help with their efforts. Firefighters will continue to maintain a community presence and provide for structure protection should it be required."
Authorities were concerned that several hotspots along the southern and southeastern portions of the burn area could potentially re-ignite dry chapparel and other fuels and roll across the firelines.
"Crews are working diligently to suppress this high priority section of fire," a forest service statement said. "In the fire area there is no previously recorded fire history, fuels remain critically dry due to drought conditions and can be difficult to suppress."
Crews expect to have the fire fully contained by midnight Wednesday, according to the forest service.
