The Ames Fire Department's looking for the cause of a house fire late Sunday night. The department says firefighters responded to an automatic alarm at about 10:30p.m. at 712 Burnett Ave. --a house owned and operated by Youth and Shelter Services. Firefighters found heavy smoke and flames at the rear of the structure. They knocked down the fire searched the house, determining that all the residents were accounted for. The cause of the fire is under investigation. Damage estimates are not available at this time.