Firefighters Tuesday morning were working to put out flames at a lumber yard in Jurupa Valley.
The incident was reported about 7:10 a.m. near the intersection of Van Buren Boulevard and Clay Street and about 4 acres have burned, according to the Riverside County Fire Department. The blaze is 10 percent contained.
Responding firefighters found an active blaze with heavy compost and sawed off wood burning.
Power lines were also down in the area.
Cal Fire and law Enforcement officers were also at the scene. Two helicopters were making water drops to calm the flames.
Lucas Spelman with Cal Fire told KTLA that the lumber yard was a major concerned for firefighters, along with a wash that is in the area.
"If fire gets in there you can imagine how much heavy brush and how long it would take us to actually get in there," he said. "It may only be 5 acres, but if it does another 5 acres, that could take us more than 24 hours to clean that whole area out."
the blaze has caused a power outage in the area and an animal shelter in Jurupa Valley had to close, Riverside County officials said in an email. The animals and personnel were not in immediate danger.
No injuries have ben reported.
The cause of the blaze is under investigation.