A pair of house fires kept crews in two different cities busy early Wednesday. On the northwest side of South Bend, firefighters were alerted by a passer-by who saw a house fire in the 700 block of North Sherman Street just before 3 a.m. When they arrived, they found flames pouring from the rear porch of the home. The fire was controlled in about 15 minutes, according to the battalion chief on scene. The home is normally occupied by a family but they weren’t in the house at the time, he said. No one was injured in the fire, which remains under investigation. About an hour earlier, crews in St. Joseph, Mich., were called to a house fire in the 1300 block of Forres Avenue. The occupants of the home were able to escape safely, but the house sustained significant damage, city 911 dispatch said. The cause of the second blaze remains undetermined.