Firefighters are battling a brush fire along Highway 39 above Glendora in the Angeles National Forest that broke out Friday afternoon, burning at least one cabin and forcing campground evacuations.
The fire was reported before 1:30 p.m. near Rincon Box Road, and consumed about 1,800 acres by 8:30 p.m., according to the Los Angeles County Fire Department.
Highway 39 was closed above East Fork Road and air units were called in to assist in the firefight. Four hundred firefighters had been called to the scene.
At least one cabin was seen in aerial video engulfed in flames. A total of four structures had burned by 9 p.m.
Coldbrook and Crystal Lake campgrounds were ordered evacuated, according to the Los Angeles County Sheriff's Department's San Dimas Station. Little Jimmy Trail Camp, West Fork Area and East Fork Area were also evacuated.
Five firefighters were evacuated with minor injuries.
It was not immediately clear how many people were affected.
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A tweet from the City of Glendora's account said the fire remained a substantial distance from the city, and there was no immediate threat to residents.
This is a developing story. Refresh for updates.