Gambill, St Lawrence Island, AlaskaApril 1951

On St. Lawrence Island, Alaska, residents and military personnel at Gambill heard a series of loud explosions over a six-month period beginning in April 1951. These blasts shook the ground and produced bright flashes, causing alarm among observers who suspected something unusual was happening offshore.

Investigators quickly determined that the explosions were not a mystery. Military intelligence concluded the sounds came from shore batteries (artillery gun emplacements) operating on the nearby Chukotskiy Peninsula, controlled by the Soviet Union. The Soviets had two confirmed and three probable coastal defense batteries, each with six guns mounted in pairs, in the area east of Gambill. The explosions were attributed to routine gunnery exercises or target practice directed at offshore positions. A radar antenna at the observation site in Gambill was also checked and found too low to have detected any actual objects in the water, making it unlikely that explosions "in the water off base of mountains" could have been observed from shore at the distances reported.

Though the case initially generated alarm and reports were submitted through military intelligence channels, the Air Force's formal evaluation was straightforward: the events were gunfire, not a UFO sighting. Military observers had recorded photos with infrared equipment, and officers noted that no radar contacts or air observations were detected during the period of the incidents. The conclusion reflected the Cold War context of the Alaska postings, where loud and unexplained disturbances were investigated carefully but ultimately traced to predictable military activities across the border. The full case file is reproduced below as held by the National Archives, comprising 15 pages.