An early morning fire yesterday on 5th Avenue and 40th Street in Altoona, has displaced several residents and caused serious damage to three townhomes. The two-alarm blaze was reported around 1:35 a.m. in the Knickerbocker neighborhood, and resulted in all three structures being condemned. A firefighter fell through the first floor into the basement but was not seriously injured, and was evaluated on the scene. The cause of the fire remains under investigation. The Salvation Army and American Red Cross were on the scene to assist the displaced residents.