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of anything amiss. Communications in 1928 were far less
ample than now.
On the sleeping mainland, only a few terrified and
stricken communities knew the reason for that stain on
the clean sea. Yet the worst disaster in the history of South-
ern California had just occurred.
At two minutes before the previous midnight, the big
St. Francis Dam, nearly 53 miles inland and 1,700 feet
above sea level, had collapsed.
The downward rush of water toward the distant ocean
took the lives of about 450 persons. ( Thirty-six years later,
the complete count is still not known, and never will be. )
Six hundred homes had been demolished. As many more
had been damaged. Eight thousand acres of productive
land had been laid waste. Unnumbered herds of livestock
and flocks of poultry had been killed. The cost of destruc-
tion was estimated to be at least $10 million.
The St. Francis Dam, in northwestern Los Angeles
Comity, was less than two years old. It had been among
the most impressive structures of its kind in the U.S. Its
concave bulwark, containing 137,000 cubic yards of rein-
forced concrete, rose 205 feet above the narrow stream
The surviving
center section of bed in San Francisquito Canyon. Its crest line measured
the dam stood 700 feet. An extension stretched 500 feet farther along the
like a headstone over west slope of the canyon. The clam was 180 feet thick at
the many who died its base, 16 feet thick at its top. Behind it, a few minutes
in the valley
that night. Later the before midnight on March 12, lay a four-mile reservoir of
grim sight was the Los Angeles ,i\later & Power Dept. The reservoir, im-
dynamited to rubble. pounding water brought south 250 miles by aqueduct from
the Owens Valley, was at its highest level. At the moment
of catastrophe, the St. Francis Dam held back 12 billion
gallons of water.
Then, without warning, the dam burst.
Its west wing collapsed first, with ex-
plosive force. Ten-thousand-ton chunks
of concrete the size of bungalows were
tumbled as far as three-quarters of a
mile by the towering dark wall of water
that lunged down San Francisquito
Canyon.
Gigantic eddies swirled at the foot of
the east section of the dam and quickly
cut away its foundations. That part of
the barrier also broke into chunks, which
All that remained slumped and lay where they fell. Only
of municipal plant the dam's center section, 205 feet high and about 100 feet
No. 2 were two
100-ton dynamos wide, resisted the tremendous pressures.
anchored to the The canyon immediately below the dam site is steep
foundation -fl,oor. and naITow and twists sharply for at least a mile. The
plunging torrent from the broken dam, rapidly swelling
to a flow greater than 500,000 cubic feet per second,
reachel a depth of 125 feet as it tore at the curves of its
tortuous channel.
90 POPULAR SCIENCE MARCH 1964