The Santa Clarita Valley was the scene of the second deadliest disaster in California's history, known as the "worst civil engineering failure of the 20th century." Shortly before midnight on March 12, 1928, the St. Francis Dam collapsed. Water from the St. Francis Reservoir coursed through San Francisquito Canyon and the Santa Clara River in a wave up to high and wide, destroying buildings in its path. By the time the floodwaters reached the Pacific Ocean near Ventura five hours later, 411 people had died. Some buildings in Newhall became makeshift morgues. After the disaster, engineer William Mulholland resigned from his position as superintendent of the Los Angeles Bureau of Water Works and Supply (now the Department of Water and Power).