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◆ CASE FILEThe facts, corroborated

The Yellow Flash over San Francisco

On a clear night in November 1948 a science teacher studying the stars from his San Francisco back yard saw a yellow light flash across the sky, turn and vanish over the fog on the Golden Gate in about seven seconds. He called the Fourth Air Force, and the Office of Special Investigations checked his story and his eyesight. This is the record of what one man saw, not a verdict on what crossed the city.

◆ THE SHORT VERSION

  • The Yellow Flash over San Francisco is a reported UAP case in San Francisco, California, United States, 29 November 1948, 21:13.
  • A science teacher studying the stars through binoculars saw a yellow light flash across the San Francisco sky, turn and vanish over the fog on the Golden Gate in about seven seconds.
  • He reported that it was too fast for a plane but did not look like a comet or a shooting star.
  • Air Force investigators found no other witness and noted that he had not been wearing his glasses at the binoculars.
  • The Air Weather Service found the light had flown straight into the wind, more than four hours after the scheduled balloon releases.
  • For this case Fractured Realities holds 1 distinct source, 1 corroborating primary document and 1 claimant on its resolved list.
  • The archive grades it L4 · OFFICIAL RECORD — a released government record names who saw it, the top of our scale, though no independent testimony sits beside that record.

Counts are resolved totals of what sources say, computed 2026-10-03; the reported details above are claims in the record, not findings. A record of reports, not a verdict on what happened.

The Yellow Flash over San Francisco
From the case file · released government record · Incident Summaries 173-233, p. 110 · Project Sign incident summary sheet for Incident 220, San Francisco, 29 Nov 1948 · released by the Department of War, 8 May 2026 ↗
EVENT DATE
29 November 1948, 21:13
LOCATION
San Francisco, California · United States
COORDS
37.77°N 122.42°W
INDEPENDENCE
L4 · OFFICIAL RECORD
SOURCES
1 distinct
CLAIMANTS
1
STATUS
Known from released government records
NUMBERS COMPUTED 2026-10-03 · RESOLVED COUNTS, NOT A VERDICT
VIEW ON ATLAS →

Robert Thatcher was in his back yard with a pair of four-power binoculars, studying the constellations on an exceptionally clear night. At about 9:13 p.m. on 29 November 1948, the Project Sign summary says, a yellow light flashed across the sky. It headed due north, then "turned North-Northwest and disappeared". It lasted about seven seconds and "appeared to be traveling too fast for a plane. However, it did not appear to be a comet or shooting star." Thatcher was an Air Force veteran who taught science at Francisco Junior High School. He telephoned Fourth Air Force headquarters to report it.

What is on the record

The Department of War released Project Sign's summary sheet and narrative for Incident 220 in the Incident Summaries 173-233 in May 2026. The sheet gives the speed only as "too fast for plane" and the shape as a "flash of light". It is still marked "Under investigation".

The Blue Book copy of the file shows where that investigation went. An agent of the Office of Special Investigations interviewed Thatcher on 13 January 1949. In that telling the object was spherical and gave a steady glow. It "did not stream fire or light". It stood 35 to 40 degrees above the horizon and passed from view over a low fog bank lying on the Golden Gate Bridge. The agent judged him intelligent and reliable. He also noted that Thatcher was near-sighted and had not been wearing his glasses at the binoculars. A canvass of the neighbourhood found no one else who had seen anything, and a try at plotting the course on a star map failed. The inquiry "failed to reveal identity of the object or produce other witnesses".

The Air Weather Service then checked balloons. It found the light had flown directly into the wind and was seen more than four hours after the scheduled releases at Alameda, Sacramento and McClellan. J. Allen Hynek's index listed Incident 220 among the possible astronomical cases, with fair or low probability.

Why it sits where it does

L4 · OFFICIAL RECORD — a released government record names who saw it. Thatcher is the only witness, and the Air Force's own search found no other. No independent testimony sits beside the file in the archive. The tier measures sourcing rather than truth. What crossed the San Francisco sky that night is not resolved here.

◆ CORROBORATION
✓38_143685_box7_Incident_Summaries_173-233 (government primary)
◆ SOURCES

Everything this file draws on, in the open — reports, not reality. Check us.

Documents & published sources

Government records, papers and journalism the archive links to this case.

government record · 1
DoW UAP Release · 1
38_143685_box7_Incident_Summaries_173-233corroboration
UNEXPLAINED LIGHTGOVERNMENT RECORD1948USA

CASE FILES STATE THE RECORD AS OUR ARCHIVE HOLDS IT — FACTS, NOT OPINION. REPORTS, NOT REALITY.

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The Yellow Flash over San Francisco — Case File · Fractured Realities