Los Angeles, December 10, 1941 — four days after Pearl Harbor, the Army's 4th Interceptor Command orders a blackout across the region from Bakersfield to San Diego after the statewide teletype system signals unidentified aircraft approaching from the sea at 7:35 PM. Fort MacArthur goes to alert. Aircraft are scrambled. Searchlights deploy 25 miles from the waterfront. Listening posts at the beach and harbor detect no motor sounds. The blackout lifts at 11:03 PM. No aircraft are identified. No official report is ever filed. The first wartime UAP-triggered blackout over the American mainland. Source: Los Angeles Times, December 11, 1941. Case Status: Insufficient Data. thinkaboutitdocs.com.
THINK ABOUTIT UFO | UAP SIGHTING REPORT
1941: City’s Black-Out Called Success
Four days after Pearl Harbor, on the evening of December 10, 1941, a yellow signal indicating the approach of enemy air raiders was flashed on the statewide police teletype at 7:35 PM. Police said the signal indicated the presence of unidentified airplanes approaching Los Angeles from the sea — but explicitly noted it did not necessarily mean they were enemy. By shortly after 8 o’clock, the Army’s 4th Interceptor Command had ordered a gigantic blackout covering the area from Bakersfield south to San Diego and eastward to Boulder City and Las Vegas, Nevada. Anti-aircraft and machine gunners scrambled to their weapons at Fort MacArthur. The Interceptor Command’s spokesman told a waiting city: “There are planes over the south of Los Angeles that are unidentified. The area will be blacked out until we can identify them.” When asked whether Army planes had been sent aloft to contact the aircraft, the spokesman said: “You can assume there have been.” Thousands of Angelenos listening for the sound of motors in the blacked-out city heard nothing. Searchlights flashed in the higher portions of Los Angeles, 25 miles from the waterfront. The blackout continued until 11:03 PM. No official identification of the aircraft was ever made. The Los Angeles Times reported it the following morning — December 11, 1941 — under the headline “City’s Black-out Called Success.” It was the first documented wartime military blackout over the American mainland triggered by unidentified aircraft. No subsequent report identified what was in the sky.
Date: December 10, 1941 (evening) — reported in the Los Angeles Times, December 11, 1941
Sighting Time: 7:35 PM (yellow signal flashed on statewide teletype); blackout ordered shortly after 8:00 PM; blackout lifted 11:03 PM
Day/Night: Night
Location: South of Los Angeles, California, USA — unidentified aircraft reported approaching from the sea; searchlights visible 25 miles from the waterfront; blackout zone covered from Bakersfield south to San Diego, east to Boulder City and Las Vegas, Nevada
Urban or Rural: Urban and regional — citywide blackout across the entire Southern California region
No. of Entity(‘s): None reported
Entity Type: N/A
Entity Description: N/A
Hynek Classification: NL — Nocturnal Light / DD (Daylight Disc equivalent for unidentified aerial objects tracked at night). The aircraft were tracked by military detection systems and observed visually via searchlight response. No structural description recorded.
Duration: Blackout in effect from shortly after 8:00 PM to 11:03 PM — approximately 3 hours. Duration of the aerial presence unknown.
No. of Object(s): Unknown — described as “planes” (plural) over south Los Angeles; “unidentified airplanes approaching Los Angeles from the sea”
Description of the Object(s): Unidentified aircraft approaching from the sea, detected by the statewide military teletype warning system. No visual description of the objects recorded. Army searchlights deployed. Army aircraft scrambled to investigate.
Shape of Object(s): Unknown — no visual description
Size of Object(s): Unknown
Color of Object(s): Unknown
Distance to Object(s): Approaching from the sea; searchlights active 25 miles from the waterfront; statewide yellow signal triggered at 7:35 PM
Height & Speed: Unknown
Number of Witnesses: Thousands of civilian Angelenos (listening, not visually observing); military personnel at Fort MacArthur; 4th Interceptor Command personnel; Army aircraft crews
Special Features/Characteristics: First documented wartime military blackout over the American mainland triggered by unidentified aircraft; four days after Pearl Harbor attack; yellow signal (enemy approach indicator) activated on statewide police teletype; 4th Interceptor Command explicitly stated “this is not a practice blackout”; Army spokesman confirmed aircraft were unidentified and intercept aircraft had been scrambled; no sound of motors could be verified by civilian or military listening posts at the beach or harbor; no official identification of the aircraft was ever made; no official report filed; precedes the February 25, 1942 Battle of Los Angeles by 76 days
Case Status: Insufficient Data — no official identification ever made
Source: Los Angeles Times, December 11, 1941 — “City’s Black-out Called Success: Southland Plunged Into Darkness as Army Reports Presence of Unidentified Aircraft; Searchlights Seen and Gunfire Reported”
Summary/Description: On the evening of December 10, 1941, four days after the Japanese attack on Pearl Harbor, the Army’s 4th Interceptor Command ordered a regional blackout across Southern California after the statewide teletype system issued a yellow signal for unidentified aircraft approaching Los Angeles from the sea. Anti-aircraft crews scrambled at Fort MacArthur. Army intercept aircraft were scrambled. Searchlights were deployed 25 miles from the waterfront. No motor sounds were detected by listening posts at the beach or harbor. No visual identification of the aircraft was made. The blackout was lifted at 11:03 PM. No official report identifying the aircraft was ever filed. The Los Angeles Times reported the event the following morning. It was the first wartime military UAP-triggered blackout over the American mainland.
Related Cases: February 25, 1942 — Battle of Los Angeles | December 9, 1941 — New York City false alarm (radar contacts, 2 days earlier) | December 8, 1941 — San Francisco radar contacts off the coast
DETAILED REPORT
The December 10, 1941 Los Angeles blackout event is the earliest documented instance of a wartime military response to unidentified aircraft over the American mainland, and its source — the front page of the Los Angeles Times dated December 11, 1941 — is primary contemporaneous newspaper documentation of the highest order. It has never received an official report identifying what the aircraft were. It predates the Battle of Los Angeles by 76 days and establishes that the pattern of unidentified aerial activity over Southern California — and the military’s inability to identify or intercept it — began not in February 1942 but in the first week of American involvement in the Second World War.
The timing is the event’s most significant contextual element. Pearl Harbor was attacked on December 7, 1941. The United States formally declared war on Japan on December 8. The Los Angeles blackout occurred on December 10 — the same day Germany and Italy declared war on the United States, completing America’s entry into the global conflict. The entire West Coast was on maximum alert, anticipating a Japanese follow-up attack. In this environment, the activation of the statewide yellow signal on the police teletype at 7:35 PM carried immediate and unambiguous military significance. This was not a drill. The 4th Interceptor Command’s public statement was explicit: “This is not a practice blackout.”
The aircraft’s origin was never established. The 4th Interceptor Command’s spokesman described them as “planes over the south of Los Angeles that are unidentified” — not Japanese planes, not enemy planes, not friendly planes. Unidentified. The signal indicated they were approaching from the sea. Army aircraft were scrambled to investigate — the spokesman confirmed this when pressed. Listening posts at the beach and harbor could not detect motor sounds. This is analytically significant: aircraft approaching a major city from the sea in 1941 would have been audible at the positions specifically designed and staffed to detect them. The listening posts heard nothing.
The searchlights deployed 25 miles from the waterfront indicate the military had a directional fix on something — searchlights are not deployed randomly in a blacked-out city. They are aimed. Whatever they were tracking at 25 miles from the waterfront was either aloft or believed to be. The discrepancy between the visible searchlight activity and the absence of motor sound at the beach listening posts is the case’s central unresolved tension.
The blackout was lifted at 11:03 PM — the 4th Interceptor Command called it “a success.” No subsequent press release, military report, or after-action document identifying the aircraft has been located in available public records. The event does not appear in standard WWII West Coast defense histories, which focus on the December 8 radar contacts and the February 1942 Battle of Los Angeles. This December 10 event — clearly documented in the Times — falls between those two bookmarks and has been effectively invisible in the record for over eighty years.
RESEARCHER’S NOTES
The First Blackout — December 10 1941 and the Missing Official Record
- Source Chain Assessment: A front-page Los Angeles Times article dated the day after the event is primary contemporaneous newspaper documentation — the same source tier as the April 5, 1941 Charleston Enterprise-Courier article for the Charleston Missouri USO encounter. The Times article quotes named institutions (4th Interceptor Command, Fort MacArthur, statewide police teletype), named positions (Interceptor Command spokesman), and specific operational details (7:35 PM yellow signal, 8:00 PM blackout commencement, 11:03 PM lift, 25-mile searchlight position). This is authoritative contemporaneous documentation.
- No Official Report — Significance: The absence of an official identification report is the most analytically significant feature of this case. Every other documented December 1941 West Coast radar contact and alert produced some official after-action assessment — even the December 8 San Francisco contacts were reviewed. The December 10 Los Angeles blackout, which was the largest and most operationally significant of the immediate post-Pearl Harbor alerts, produced no publicly available official identification. This could mean: (1) the aircraft were identified as friendly and classified; (2) they were identified as enemy and suppressed; (3) they were genuinely unidentified and the matter was closed without resolution in the chaos of the first week of war; or (4) an official report exists in classified or restricted archives not yet publicly released.
- The Listening Post Silence: The specific detail that listening posts at the beach and harbor could not verify the sound of gunfire or motors is a standard 1941 acoustic observation protocol detail — and it is anomalous. Aircraft approaching Los Angeles from the sea in December 1941 at any altitude below 20,000 feet would have been audible to trained beach and harbor listening posts. The absence of sound is consistent with either extremely high altitude, a non-conventional propulsion signature, or the complete absence of the aircraft from the airspace despite the teletype signal and searchlight response.
- The Battle of Los Angeles Connection: The February 25, 1942 Battle of Los Angeles — 76 days later, same city, same 4th Interceptor Command, same pattern of unidentified aerial objects from the sea with no physical identification made — has received decades of research attention. The December 10, 1941 event, which established the same pattern first, has received almost none. The two events should be analyzed as a series, not as isolated incidents. The December 10 blackout established the operational response template that the military would repeat — with much greater force — on February 25.
On the evening of December 10, 1941 — the day America went to war with Germany and Italy, four days after Pearl Harbor — something approached Los Angeles from the sea and triggered the largest regional blackout in American history to that date. The 4th Interceptor Command scrambled aircraft to intercept it. Searchlights swept the higher portions of the city, 25 miles from the waterfront. Listening posts at the beach and harbor heard nothing. The blackout lasted until 11:03 PM. No official report ever identified what was in the sky. The Los Angeles Times printed it on page one the next morning and called the blackout a success. Whatever approached Los Angeles from the Pacific on December 10, 1941 was never identified. It is the first entry in the Southern California wartime UAP record, and it has no resolution.
Los Angeles Times December 11th, 1941
Southland Plunged Into Darkness as Army Reports Presence of Unidentified Aircraft; Searchlights seen and gunfire reported
A gigantic black-out, covering the area from Bakersfield south to San Diego and eastward to Boulder City and Las Vegas, Nev., went into effect shortly after 8 o’clock last night on orders from the Army Fourth Interceptor Command. It continued until 11:03 p.m.
As Los Angeles went dark amongst considerable confusion and uncertainty, The Interceptor Command announced, “this is not a practice black-out.”
A yellow signal, indicating the approach of enemy air raiders, was flashed on the statewide teletype at 7:35 p.m.. Police said the signal indicated the presence of unidentified airplanes approaching Los Angeles from the sea but did not necessarily mean they were enemy.
FORT GUNNERS SCRAMBLE TO POSTS
Anti-aircraft and machine gunners scrambled to their weapons at Ft. Mac Arthur, which was promptly placed on alert basis.
Reports that the sound of gun fire could be heard could not be verified from listening posts at the beach or at the harbor.
Definite indication that the Interceptor Command meant business by calling for the black-out was contained in a statement from a spokesman who said:
“There are planes over the south of Los Angeles that are unidentified. The area will be blacked out until we can identify them.”
PLANES SENT UP TO INVESTIGATE
When asked if Army planes had been sent aloft to contact these aircraft the spokesman said: “You can assume there have been.”
Thousands of Angelenos, listening for straining ears for sounds of aircraft, were unable to distinguish sounds of motors, however.
A few minutes after the black-out was ordered, the flashing of what appeared to be Army searchlights was visible in the higher portions of Los Angeles, 25 miles from the water front.
Headquarters of the Fourth Interceptor Command, calling the blackout a success, said they a had a report that unidentified planes were in the vicinity of Los Angeles.
remainder of article unavailable
