Update, 9 a.m.
The Rock Fire burned 39 acres and was 40 percent contained as of Sunday morning, according to Cal Fire. The Mustang Fire remains at 37 acres and 80 percent containment.
Update, 9:30 p.m.
Crews reached 35 percent containment on the Rock Fire, according to Cal Fire SLO. The Mustang Fire is 80 percent contained.
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Firefighters responded to multiple vegetation fires Saturday afternoon in Paso Robles.
Cal Fire SLO first reported a blaze, called the Rock Fire, at 14140 Chimney Rock Road shortly before 3 p.m.
Within 30 minutes, the fire grew to 15 acres and additional engines were ordered, according to Cal Fire.
Less than an hour later, Cal Fire reported a second blaze at 3250 Mustang Springs Road, also in Paso Robles.
Crews were able to stop forward progress on the fire near Mustang Springs Road, which burned 27 acres and was 50 percent contained by 6 p.m.
Firefighters also made good progress on the Rock Fire, which expanded to 25 acres and was 20 percent contained by 5 p.m.
Cal Fire reported that multiple agencies responded to the Rock Fire, including 10 engines, four crews, two bull dozers, four air tankers and one helicopter.