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NPS Form 10-900 OMB No. 1024-0018
(Rev. 8-86)
United States Department of the Interior
National Park Service

National Register of Historic Places
Continuation Sheet

Section number 8 Page 7

St. Francis Dam (Site of), Los Angeles County, California — Narrative Statement of Significance
[continued]
Mulholland and his assistant chief engineer Harvey Van Norman hurriedly departed Los Angeles for San Francisquito Canyon,
arriving at the dam by late morning. After inspecting the dam for about an hour and a half, Mulholland, Van Norman and
Harnischfeger concluded that the water leaking from under the abutment was clear, and was only becoming turbid as it cascaded down
the hillside. Satisfied that the leak presented no immediate concerns, Mulholland and Van Norman returned to Los Angeles shortly
after noon. [Figures 5, 6]

The first indication of an impending catastrophe at the St. Francis Dam was seen at between 8:30 and 9:00 PM that evening by Ray
Silvey, night-shift operator at Powerhouse No. 1. As he was driving to work on the road beside the reservoir on the way to his 11:00
PM shift, Silvey noted a foot-high crack on the road “just upstream of the dam.” Although he could not have have recognized its
significance, this was most likely the initiation of a landslide on the dam’s eastern abutment. Then, shortly before midnight, Ace
Hopewell, the last Powerhouse No. 1 employee to drive past the dam that evening, stopped his motorcycle when he heard what to
him sounded like a landslide in the distance. In doing so, Hopewell became one of only a handful of surviving witnesses to the sight
or sound of the St. Francis Dam failure. [Outland, 1963: 76]

The first notice of the dam’s collapse came at 11:57:30 PM, when the operators at Powerhouse No. 1 detected an abrupt voltage drop
on their instruments. They were seeing the destruction of the Southern California Edison Company’s electric transmission lines
strung across San Francisquito Canyon, a few hundred feet downstream from the dam. At the same instant, lights dimmed
momentarily in Los Angeles, as the Edison Company’s substation at Saugus 9.5 miles to the southwest of the dam shorted out from
the overload. [Outland, 1963: 77]

Within minutes after midnight, Powerhouse No. 2 and the downstream DWP employee’s village in San Francisquito Canyon were
engulfed by a wall of water, silt and debris over 100 feet in height moving down the canyon at 18 miles per hour. The powerhouse, a
massive poured-in-place concrete building constructed only eight years earlier, was completely erased, and 25 of the department’s 28
employees and their family members living in city-owned homes immediately below the dam perished. They would be only the first
of hundreds of casualties to follow, as the inundation ran its course to the Pacific Ocean, 54 miles away.

As the deluge worked its way southwards through the farmsteads of lower San Francisquito Canyon, it suspended within its bulk a
massive and destructive conglomeration of silt and debris, including rocks, trees, buildings and barbed wire. Less than an hour after
the dam’s failure, the wave reached Castaic Junction, a hamlet adjacent to the Ridge Route over the Tehachapi Mountains. Several
more lives were claimed at that location, and the main highway connecting Los Angeles and Bakersfield was buried under water, silt
and debris. From Castaic, the main wave turned westwards, into the upper reaches of the Santa Clara River Valley. [Outland, 1963:
87-88] [Figure 7]
The cascade of electrical power failures that began shortly before midnight, minutes after the dam’s collapse, continued as the flood
waters roiled downstream. The utilities initially compensated, even as the high-tension lines operated by the Los Angeles Bureau of
Power and Light and the Southern California Edison Company were being cut in rapid succession by the waters.
Finally, when the Edison Company substation at Saugus was inundated at 12:45 AM, residents of Ventura, Santa Barbara and much
of Los Angeles counties found themselves in darkness. Still, the likely cause of such an unusual set of system failures remained
unappreciated by the utility dispatchers who were witnessing it. A general alarm had not been sounded. [Outland, 1963: 91-93]
The magnitude of the calamity came into sharp focus at 1:09 AM, over an hour after the dam’s collapse, when Powerhouse No. 1
reported an empty St. Francis Reservoir to the Department of Water and Power offices in Los Angeles. Efforts on the part of the
DWP to alert residents of the Santa Clara Valley now began in earnest, but would be hampered by the widespread power outages.