VIDEO: Investigators are looking into what sparked a house fire on Arnett Boulevard Thursday night. A mother and her child were upstairs in the home when she heard the smoke alarm going off around 9:30 p.m. Thursday. Firefighters say they arrived to find heavy fire on the first floor that was quickly spreading to the second floor. Rochester Deputy Fire Chief Darryl Winter says smoke detectors were essential for a safe escape in this case. "Here is a primary example, if the smoke alarm doesn't go off, she's upstairs before they even notice the smoke and the fire probably engulfs the whole first floor" Chief Winter said. Everyone made it out of the house. No one was hurt. The house has severe damage.