The city of Seattle also imposed a blackout of all buildings and vehicles, and owners who left the lights on in their buildings had their businesses smashed by a mob of 2,000 residents. Rumors that a Japanese aircraft carrier was cruising off the coast of the San Francisco Bay Area resulted in the city of Oakland closing its schools and issuing a blackout civil defense sirens mounted on patrol cars from the Oakland Police Department blared through the city, and radio silence was ordered.
In Juneau, Alaska, residents were told to cover their windows for a nightly blackout after rumors spread that Japanese submarines were lurking along the southeast Alaskan coast. continent were acknowledged as realistic possibilities. In the months following the Imperial Japanese Navy's attack on Pearl Harbor in Hawaii on December 7, 1941, and the United States' entry into World War II the next day, public outrage and paranoia intensified across the country and especially on the West Coast, where fears of a Japanese attack on or invasion of the U.S. Office of Air Force History attributed the event to a case of "war nerves" triggered by a lost weather balloon and exacerbated by stray flares and shell bursts from adjoining batteries. When documenting the incident in 1949, the United States Coast Artillery Association identified a meteorological balloon sent aloft at 1:00 am as having "started all the shooting" and concluded that "once the firing started, imagination created all kinds of targets in the sky and everyone joined in".
Newspapers of the time published a number of reports and speculations of a cover-up to conceal an actual invasion by enemy airplanes. Initially, the target of the aerial barrage was thought to be an attacking force from Japan, but speaking at a press conference shortly afterward, Secretary of the Navy Frank Knox called the purported attack a "false alarm". entered World War II in response to the Imperial Japanese Navy's surprise attack on Pearl Harbor, and one day after the bombardment of Ellwood near Santa Barbara on 23 February. The incident occurred less than three months after the U.S. The Battle of Los Angeles, also known as the Great Los Angeles Air Raid, is the name given by contemporary sources to a rumored attack on the continental United States by Imperial Japan and the subsequent anti-aircraft artillery barrage which took place from late 24 February to early 25 February 1942, over Los Angeles, California.