About two dozen homes have been destroyed this week. At a briefing late Wednesday, Capt. Dave Allen said that the fires had spread over 9,000 acres.
The most destructive was the Carlsbad fire. Carlsbad Mayor Matt Hall said the fire destroyed four single-family homes, an apartment complex with 18 units, two commercial buildings and damaged six homes.
The mayor estimated losses at $22.5 million so far. But he credited firefighters with preventing even greater loss.
"We literally saved hundreds of homes," he said.
In San Marcos, the Cocos fire was completely uncontained early Thursday. Officials said 21,000 people were advised to evacuate and called the blaze "erratic."
The fire was reported Wednesday afternoon.
The Tomahawk fire at Camp Pendleton, which began Wednesday, was reported to be 25 percent contained. Several hundred people at Pendleton, a major U.S. Marine base on the west coast, were forced out of their homes or workplaces.
The Bernardo fire, which began Tuesday, was 50 percent contained Thursday and did not grow overnight. The fire threatened hundreds of homes when it started but firefighters cut lines in the brush to keep it from spreading while water was dropped from the air.
Carlsbad Fire Chief Michael Davis said each fire is being investigated for arson.
"It's been a tough day," San Diego County Supervisor Dianne Jacob said late Wednesday. "We are getting help, but the fight is far from over."