The Rock Fire reached 40 percent containment, while the simultaneous Mustang Fire remains 80 percent contained Sunday.
CAL FIRE SLO says both fires started within an hour of each other Saturday afternoon. The Rock Fire started at 14140 Chimney Rock Road near Lake Nacimiento and the Mustang Fire began at 3250 Mustang Springs in Paso Robles.
Crews believe the acreage hasn’t changed from 39 acres.
"Significant mop up is still required due to large trees and heavy vegetation," CAL FIRE SLO tweeted about the Rock Fire.
The Mustang Fire is expected to reach full containment Sunday as well.