80 Years Ago Today: St. Francis Dam Collapse


The collapse of the St. Francis Dam ranks as the worst civil engineering disaster of the 20th century and remains the second-greatest loss of life in California behind the San Francisco earthquake and fire of 1906. And it began a few minutes before midnight on March 12, 1928.

Built under the supervision of William Mulholland, the St. Francis Dam’s 185-foot concrete wall spanned San Francisquito Canyon about five miles northeast of what is now Santa Clarita. Behind it stood some 12 billion gallons of water.

In the first year after its completion in 1926, the dam hinted at its potential flaws in the form of cracks and leaks that Mulholland would inspect and dismiss as normal for a dam of that size. It was filled to capacity for the first time on March 7 and new cracks and leaks almost immediately appeared, again disregarded by Mulholland. On the morning of March 12 still more fresh cracks and leaks presented and for the last time Mulholland pronounced them normal and the dam entirely safe.

Less than 12 hours later it disintegrated, sending a 125-foot-high wall of water earth, rock and debris south down the canyon, destroying everything in a path that turned west at what’s now modern day Newhall and Valencia into the Santa Clara River Valley where the flood continued on for 54 miles. When it reached the Pacific Ocean at Montalvo some 5.5 hour later, the waters were almost two miles wide and moved at 5 mph.


The current death toll is estimated by various sources between 450-600, but the exact number of victims will never be known. The official number killed was listed as 385 in 1928, but that number doesn’t much take into account the untold numbers of itinerant workers lost who worked and camped along the flood path. In addition, many bodies were unrecovered from having been swept out to sea, though some were found as far south as the Mexican border. Bodies across the Santa Clara River Valley continued to be regularly discovered into the mid-1950s, and as recently as 1992 the remains of another victim was unearthed near Newhall.

An inquest concluded that the dam’s failure was caused by what was a then-undetectable instability of the rock formations upon which it was built and determined the disaster to be the fault of the governmental organizations that supervised the dam’s construction. Mulholland may have been legally cleared, but personally he never forgave himself, retiring from the LADWP and retreating into isolation until his death in 1935. Nor did he try to shirk blame. “If there was an error in human judgment,” he said, “I was the human and I won’t try to fasten it on anyone else.”

Happening: Santa Paula Oil Museum exhibit — 80th Anniversary St. Francis Dam Disaster, March 16- July 27.

Information and photos obtained from:

• St. Francis Dam Wiki
• Sespe.com’s Dam Disaster page

One thought on “80 Years Ago Today: St. Francis Dam Collapse”

  1. I just happened to be drinking coffee out of my “St. Francis Dam Disaster – Seventy Fifth Anniversary” mug when I saw this post. While obviously a tragic tale, it is to my mind one of the most fascinating, under-reported and misunderstood chapters in California history.

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