March 1928: St. Francis Dam Disaster Sends Water on a Rampage Across Southern California More than 450 people were killed in the March 1928 St. Francis Dam collapse, a civil engineering failure that unleashed an avalanche of water across Southern California By Jonathan Lloyd By Jonathan Lloyd This article was originally published March 11, 2019. In March 1928, the worst civil engineering failure in California history killed more than 450 people when a wall of water carved a path of staggering destruction from a canyon north of Los Angeles to the coast. Click here for historic photos of the St. Francis Dam and the aftermath of its collapse.