In early February 1942, the United States was in full war mode just two months after the Japanese attack on Pearl Harbor in Hawaii. What Japan was capable of doing and how the war would progress was then a huge unknown for most Americans and the country was on edge. On the night of February 23, a Japanese submarine conducted what became the only bombing of the continental United States when it fired 13 shells from offshore into an oil facility near Santa Barbara. This only further stoked fears among Southern Californians of a massive Japanese assault on their coastline. Military intelligence instructed coastal defenses to prepare for an imminent attack.
At 2:00 a.m., on the morning of February 25, 1942, U.S. Army radar reportedly detected an unidentified object or objects about 120 miles off the coast of Los Angeles. Military authorities in the Los Angeles area ordered all air defenses fully manned and air raid alarms and a full blackout initiated across the city. Los Angeles was jolted out of bed by the screaming sirens, but, ignoring the blackout rules, hundreds of thousands of residents snapped on lights and spilled into the streets to watch searchlights sweeping the sky. Thousands of volunteer air raid wardens grabbed helmets and boots to rush to their stations.
At 3:00 a.m., the unidentified object or objects were reported to be just off the coast of Santa Monica. Anti-aircraft units were given permission to fire on sight. At 3:07 a.m., anti-aircraft units in Santa Monica, reporting the sighting of enemy aircraft, began firing into the sky. Shortly thereafter, anti-aircraft units across the Los Angeles area joined in firing into sky. In addition to sweeping searchlights, orange tracer shells began streaming into the night sky across the city.
Fear and panic quickly spread throughout the city. As smoke from exploding shells began collecting in the sky, civilians and army gunners both reported sightings of enemy aircraft, falling bombs and Japanese paratroopers. A report came in claiming that a Japanese aircraft had crashed in Hollywood. Frightened drivers, speeding through darkened streets, collided with one another, resulting in three traffic fatalities. As many as three other persons were reported to have died from fatal heart attacks.
The barrage of fire over the city continued from more than an hour. When a cease-fire was ordered, anti-aircraft gunners had expended more than 1,400 rounds of ammunition, causing quite a bit of damage to structures on the ground. Many Angelenos believed that they were going to see a Japanese invasion force lying offshore when daylight broke.
By daylight, however, no Japanese ships lay off the coast, no downed enemy aircraft were found and no enemy bomb damage was reported. Confused and embarrassed authorities, with no explanation for the morning’s events, focused instead on arresting 20 Japanese-Americans for allegedly trying to signal the mysterious enemy aircraft.
Within days, the U.S. Secretary of the Navy, Frank Knox, admitted that the whole incident to have been a mistake. The U.S. Secretary of War, Henry Stimson, however, stated that 15 enemy aircraft had appeared over Los Angeles. Stimson later retreated from that position.
So, what did military gunners actually shoot at? Explanations for what had spooked gunners ranged from a false alarm to meteorological balloons to UFOs. An official investigation, however, could not clearly determine the exact cause. The incident turned out to be the only serious military action to occur over a continental U.S. metropolitan area during World War II.
Many years later, in 1983, the Office of Air Force History, after conducting their own study of the 1942 events,* concluded that U.S. military defenses in California were already nervously poised for action, partly due to the attack from the Japanese submarine off the coast of Santa Barbara. The office also noted that meteorological balloons had been released prior to the incident that, with attached lights and their silvery color, may have been mistaken for aircraft.
* The Army Air Forces in World War II, prepared under the editorship of Wesley Frank Craven and James Lea Cate. Volume 1, pp. 282-286. Office of Air Force History, Washington, D.C.