The Johnstown Flood (1926)

Set in 1889, an engineer (George O'Brien) for a lumber company is engaged to the owner's (Anders Randolf) daughter (Florence Gilbert). He warns the father of the imminent failure of the dam but he is ignored. Directed by Irving Cummings (DOWN ARGENTINE WAY), this is a fictionalized version of the Great Flood Of 1889 in Johnstown, Pennsylvania that killed over 2,000 people. This is an early example of what became known as the disaster movie genre in the 1970s. The special effects are quite striking, even some 90 years later. Character development is superficial but the handsome George O'Brien and lovely Janet Gaynor (in her first major role) are very appealing which is enough for a movie like this. With Paul Nicholson, Paul Panzer and reputedly a young Clark Gable is in the background somewhere in the saloon sequence but I didn't catch him.