On the evening of February 24, 1942, an anti-aircraft barrage of more than 1,440 rounds is launched at what is initially thought to be a Japanese aerial attack on the City of Angels. Five civilians die – three from traffic accidents spawned by the chaos and two from heart attacks.

What, if anything, is being fired upon remains a mystery. Theories include weather balloons, UFOs, birds, or just jitters by Angelenos with Pearl Harbor still a fresh memory and, even fresher, a Japanese submarine torpedoing a Santa Barbara oil field on February 23.

Regardless of cause, air raid sirens first blare at 7:18 p.m. Thousands of air raid wardens go to their posts throughout Los Angeles County. That alert is lifted at 10:23 p.m. Tensions ease. Then, after midnight, all hell breaks loose. From “Chapter 8: Air Defense of the Western Hemisphere” by William Goss, The Army Air Forces in World War II, Vol. 1 published in 1983:

“Radars picked up an unidentified target 120 miles west of Los Angeles. Antiaircraft batteries were alerted at 2:15 am and were put on Green Alert—ready to fire—a few minutes later. The (Army Air Force) kept its pursuit planes on the ground, preferring to await indications of the scale and direction of any attack before committing its limited fighter force. Radars tracked the approaching target to within a few miles of the coast, and at 2:21 am the regional controller ordered a blackout. Thereafter the information center was flooded with reports of ‘enemy planes,’ even though the mysterious object tracked in from sea seems to have vanished. At 2:43 am, planes were reported near Long Beach, and a few minutes later a coast artillery colonel spotted ‘about 25 planes at 12,000 feet’ over Los Angeles. At 3:06 am a balloon carrying a red flare was seen over Santa Monica and four batteries of anti-aircraft artillery opened fire, whereupon ‘the air over Los Angeles erupted like a volcano.’ From this point on reports were hopelessly at variance.”

Not the least at variance are the media reports. According to the Los Angeles Herald Examiner a witness puts the number of planes at 50. Three are shot down over the ocean. A battery near Vermont Ave. takes out another. “Air Battles Rages Over Los Angeles” is the headline of the Examiner’s “War Extra.” The normally more staid Los Angeles Times says:

“Roaring out of a brilliant moonlit western sky, foreign aircraft flying both in large formation and singly flew over Southern California early today and drew heavy barrages of anti-aircraft fire – the first ever to sound over United States continental soil against an enemy invader.”

In Washington D.C., Navy Secretary Frank Knox says: “As far as I know the whole raid was a false alarm and could be attributed to jittery nerves.” Secretary of War Henry Stimson says 15 unidentified aircraft were over Los Angeles  — possibly commercial aircraft operated by the enemy from secret fields in California or Mexico or light planes launched from Japanese submarines. Their goal is to determine the location of anti-aircraft defense or damage civilian morale, Stimson says.

Returning to The Army Air Forces in World War II, Vol. 1:

“Probably much of the confusion came from the fact that anti-aircraft shell bursts, caught by the searchlights, were themselves mistaken for enemy planes. In any case, the next three hours produced some of the most imaginative reporting of the war: “swarms” of planes (or, sometimes, balloons) of all possible sizes, numbering from one to several hundred, traveling at altitudes which ranged from a few thousand feet to more than 20,000 and flying at speeds which were said to have varied from “very slow” to over 200 miles per hour, were observed to parade across the skies. These mysterious forces dropped no bombs and, despite the fact that 1,440 rounds of anti-aircraft ammunition were directed against them, suffered no losses.”

After the war, Japan says it has no planes in the area at the time of the “raid.” The Army Air Forces in World War II, Vol. 1 posits weather balloons as the most likely explanation. A photo from the Los Angeles Times has been used to “prove” it is an extraterrestrial craft. Another explanation appears in an article attributed to the veteran Los Angeles newsman Matt Weinstock in which he interviews a man who says he served in one of the anti-aircraft batteries:

“Early in the war things were pretty scary and the Army was setting up coastal defenses. At one of the new radar stations near Santa Monica, the crew tried in vain to arrange for some planes to fly by so that they could test the system. As no one could spare the planes at the time, they hit upon a novel way to test the radar. One of the guys bought a bag of nickel balloons and then filled them with hydrogen, attached metal wires, and let them go. Catching the offshore breeze, the balloons had the desired effect of showing up on the screens, proving the equipment was working. But after traveling a good distance offshore and to the south, the nightly onshore breeze started to push the balloons back towards the coastal cities. The coastal radar’s picked up the metal wires and the searchlights swung automatically on the targets, looking on the screens as aircraft heading for the city. The ACK-ACK started firing and the rest was history.”

TOP Photo: Observation squadron aims anti-aircraft gun at a Douglas plane during a military show for National Defense Week, Los Angeles, 1940. Photo Credit: Los Angeles Daily News Negatives. Department of Special Collections, Charles E. Young Research Library, University of California at Los Angeles.