St. Francis Dam Disaster - 75th Anniversary

Minutes before midnight on the chilly evening of March 12, 1928 the St. Francis Dam failed. The dam's 200-foot concrete wall crumpled and collapsed, sending billions of gallons of raging flood waters down San Francisquito Canyon, about five miles northeast of what is now Santa Clarita. The avalanche of water swept 54 miles down the Santa Clara River Valley to the sea. An exact death toll was never arrived at but more than 450 people perished in the disaster.

The St. Francis Dam Disaster is second only to the San Francisco Earthquake and Fire of 1906 in the history of California disasters. Aside from the similarity in names and comparable death tolls, the disasters had little in common. The San Francisco Earthquake is referred to as an act of God while the St. Francis Dam Disaster can be attributed to human error. It was the greatest American civil engineering failure of the twentieth century.

The dam construction began in 1924 by William Mulholland and a group of engineers and construction crews working for the forerunner of the Los Angeles Department of Water and Power. The stated purpose of the dam was to provide an additional 38,000 acre-feet of storage for the Los Angeles/Owens River Aqueduct water for a growing and thirsty Los Angeles. The impressive dam was completed in June of 1926. After its failure, Mulholland accepted blame for the collapse.

One current explanation for the collapse is because the dam's eastern side sat on an ancient landslide that partially reactivated and plowed into the dam "like a bulldozer", causing a chain reaction. Given the geological knowledge at the time, Mulholland and his designers were not aware of that fatal flaw. Another contributing factor was the additional 20 feet to the height of the dam beyond what it was originally designed to handle. These 20 feet added approximately one third of the capacity of the reservoir.

As a result of its failure 1,200 homes were demolished, 10 bridges were washed out, power was knocked out over a wide area and the communities of Castaic, Piru, Fillmore and Santa Paula were paralyzed. In addition to the reported deaths there were many bodies that were never found. The city of Los Angeles would pay damage claims totaling more than 4.8 million dollars.