People were taking shelter in San Diego's Qualcomm Stadium, although those with pets were told to stay in the carpark as animals are banned from the stadium.
One San Diego firefighter described the scene as like the end of the world.
"It was nuclear winter. It was like Armageddon," he said.
Firefighters think that at least one of the fires, in Orange County, was set.
Roxanne Provaznik, a spokeswoman for the California department of forestry, said that the fire was spreading unchecked.
State of emergency
Some residents were reluctant to leave their homes and firefighters said this delayed their efforts to contain the blaze.
Winds of up to 112kph also scattered embers on to dry brush, spawning more fires. California officials have asked for help from fire departments in other states.
|The fires started over the weekend [AP]|
Arnold Schwarzenegger, the governor of California, had declared a state of emergency in the seven affected counties, opening the way for government aid.
The mayor of San Diego said 1,500 national guardsmen would focus on preventing looting and help with evacuations.
Among those who were evacuated were hundreds of patients moved by school bus and ambulance from a hospital and nursing homes, many still in their hospital gowns and wheelchairs.
In Orange County, a 1,049-inmate jail was evacuated because of heavy smoke.
US marine officials at Camp Pendleton opened the base to residents.
A blaze threatening the wealthy Malibu area might have been caused by power lines brought down by the strong winds.