Despite the efforts of engineer John Parke, the South Fork Dam does break. The ensuing flash flood sweeps up a vast, moving wall of debris: mud, rocks, trees, fragments of bridges and smashed-up houses. Residents in Johnstown, including Reverend H.L. Chapman and his family, have mere seconds to flee to higher ground as the floodwaters and debris crash into their homes. The lucky ones find themselves clinging to rooftops amid the raging waters, fighting to survive. See Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.