The causes of both fires were under investigation.
About 40 units of the 187-unit complex were destroyed, Fire Department spokesman Tony Espinosa said. About 30 more had water damage.
Three firefighters suffered heat exhaustion and smoke inhalation.
A temporary shelter for displaced residents was set up at a school. Red Cross officials said they expected to handle as many as 400 people.
Sixty firefighters took about two hours to control the blazes, which were reported about 11:30 a.m. at the La Serena apartment complex, Espinosa said. When firefighters arrived, one fire had spread to an attic and swept through a long, two-story building.
Fire later erupted about 40 yards away at a separate building in the complex of 10 buildings.
``It looks like the fire spread either through embers or through a building in the back,'' Espinosa said.
