A cluster of four lightning-sparked wildfires in northeastern San Diego County now covers 2,352 acres.
The largest blaze in the Vallecito Complex is 1,400 acres and is only 5 percent contained Tuesday.
The California Department of Forestry and Fire Protection says firefighting costs have topped $800,000.
Officials say there is a threat to electrical distribution lines in Grapevine Canyon that serve the communities of Borrego Springs, Warner Springs and Ranchita.
The area is 50 miles northeast of downtown San Diego.
Elsewhere in Southern California, a 269-acre fire in Joshua Tree National Park is 35 percent contained, and San Bernardino County firefighters have a 60-acre blaze 60 percent contained near Needles. Embers from that lightning-sparked blaze blew across the Colorado River and 280 acres are ablaze on the Arizona side.
