24 February 1942, nearly three months after the attack at Pearl Harbor, an Anti-Aircraft Artillery action occurs in the skies above Los Angeles, California. Initially, the target of the barrage was thought to be attacking Japanese aircraft, however, there is no evidence that Japanese aircraft were present at all. Officially the incident has been explained as being caused by "war nerves" and a lost weather balloon. There are, of course, alternative explanations.
Anti-aircraft guns and spotlights comb the sky above Los Angeles.
On the night of 23 February 1942, the Imperial Japanese Submarine I-17, captained by Commander Kozo Nishino, bombarded the Ellwood Oil field in Goleta, California near Santa Barbara with her 14-cm deck gun. Known as the Bombardment of Ellwood, the incident caused only $500 worth of property damage and resulted in no casualties, but it triggered fears of a Japanese invasion of the West Coast and would eventually lead to President Roosevelt's decision to intern Japanese-Americans.
The I-17 was a B1-type Japanese Submarine, just like the I-15 depicted in this photo.
On 24 February, with tensions high following the previous night, Naval Intelligence issued a warning that an attack on coastal California could be expected within the next ten hours. Reports of flares and signal lights in the vicinity of defense manufacturing plants caused an alert to be called at 7:18 pm, but it was lifted at 10:23 pm. Early on the morning of the 25th, activity would resume. Air raid sirens sounded at 2:25 am throughout Los Angeles County, a blackout was ordered, and thousands of Air Raid Wardens assumed their posts. At 3:16 am, the 37th Coast Artillery Brigade began firing .50 caliber machine guns and 90 mm anti-aircraft guns at reported aircraft. Over 1400 shells would be expended before the "all clear" was called at 4:14 am.
A 90 mm M1 Anti-aircraft gun. This one is in Okinawa, 1945.
Several Buildings and vehicles were damaged by shell fragments, and there were five civilian deaths as an indirect result of the anti-aircraft fire. Three civilians died in car accidents, and two of heart attacks attributed to the stress. The incident became front page news across the nation.
Only hours after the incident, Secretary of the Navy Frank Knox held a press conference where he declared the entire incident a false alarm due to anxiety and war nerves. However this statement was seemingly contradicted the next day by U.S. Army General George C. Marshall, who attributed the incident to a psychological warfare campaign being perpetrated by the Japanese (though many believe General Marshall's statement was mere speculation). Regardless, many contemporary news sources suspected some kind of cover-up. Speculation included rumors of a Japanese airbase in Mexico or of Japanese aircraft carrier submarines lurking off the coast. Still others thought the event had been staged for political reasons.
The LA Times photo spread of the incident from 26 February 1942.
After the war, the Japanese government issued a statement declaring that no airplanes had been flown over Los Angeles during the war. In 1949, the United States Coastal Artillery Association conducted research which concluded that the incident had been caused by a stray weather balloon, asserting that once one trigger happy gunner started shooting, imaginations ran wild and everyone joined in. Research conducted by the U.S. Office of Air Force History in 1983, concurred with the 1949 report, attributing the entire incident to war anxiety and a lost weather balloon.
Many UFO conspiracy theorists suspect a thwarted extraterrestrial invasion to be the cause. This is mostly based on a photo published by he Los Angeles Times on February 26, 1942, which appears to show searchlights focused on an alien spaceship. However, this photo had been heavily modified by photo retouching prior to publication and is not entirely trustworthy.
Of course, in the Fallout timeline, aliens may very well have been present at the Battle of Los Angeles. Could the Zetans have been responsible for the incident?