No residents or firefighters were injured, officials said, but a pet cat that lived in one of the homes perished in the fire.
The fire erupted about 3:29 a.m. in the rear laundry room of a two-story Victorian home in the 900 block of 24th Street near Market Street, officials said. Battalion Fire Chief Emon Usher said the fire started as a result of an electrical problem.
The first of 50 firefighters who were on scene by 3:33 a.m. found the first house engulfed in flames and smoke and within five minutes a third alarm was called.
Usher said the fire initially spread to a two-story Victorian duplex to the left and then caused some exposure damage to a house on the right of the original site. He said the houses being so close together prompted the extra alarms.
Firefighters, who were hampered by arcing power lines, had the fires under control at 4:40 a.m., Usher said.
Five people were living in the house where the fire started, four in the home to the left and three in the home to the right, officials said. They were being provided temporary shelter by the Red Cross.
Usher estimated damage at between $500,000 and $800,000. He said the house where the fire started is uninhabitable but that the residents of the other two homes could eventually return.