Seattle, Washington · November 3, 1944
On this date in 1944 Japan began an explosive balloon campaign against the U.S. and Canada. Over the next five months the Special Balloon Regiment of the Japanese Army launched about 9,300 hydrogen-filled rubberized-silk or paper “fire balloons” (fūsen bakudan, lit. “balloon bomb”), or Fu-Go’s as they were known in Japan, from the esstern shore of Honshū Island. Made mostly by school girls and carried by the high-altitude jet stream, the 32‑ft diameter “secret weapons” carried a container of magnesium flash powder and 33‑lb high-explosive antipersonnel bombs.
Crude but ingenious, building a balloon that carried 1,000 lb of gear and that could survive a 5,000‑mile trip across the Pacific Ocean, then automatically drop its payload was technically challenging. A hydrogen balloon expands when warmed by the sunlight and rises, then contracts when cooled at night and falls. Japanese engineers devised a control system driven by an altimeter that discarded ballast (sandbags) or vented hydrogen to maintain altitude (30,000–38,000 ft).
Some 285 to 300 Japanese fire balloons reportedly reached the North American continent, some floating inland as far as Michigan. Most of the fire balloons fell harmlessly into the Pacific Ocean or self-destructed before reaching the mainland. However, pieces of paper from a Japanese fire balloon were found in a Los Angeles street. When the balloons were sighted near the West Coast or over land, aircraft from the U.S. Navy or U.S. Army Air Forces flew intercept missions to shoot them down.
The only known victims of one of these devices were six Oregon picnickers who were killed on May 5, 1945, when they tried to move a downed balloon and the antipersonnel mine exploded. One balloon-caused brush fire triggered a shutdown of the Hanford, Washington, atomic processing facility, ironically delaying work on the production of material for the atomic bomb that was later dropped on Nagasaki, Japan.
Following two news media accounts in early January 1945 of a “balloon mystery,” the U.S. Office of Censorship enforced a news blackout on the subject to reduce the chance of panic among West Coast residents and to deny the Japanese any information on the success of their launches. Discouraged by the apparent failure of their effort, the Japanese halted their balloon attacks in April 1945.
Japan’s Fire Balloon Campaign and Other West Coast Attacks
Left: A Japanese balloon bomb reportedly discovered and photographed by the U.S. Navy in Japan. Large indoor spaces such as sumo halls, sound stages, theaters, and hangers were required for balloon assembly. The firebombing of Japanese cities by U.S. B‑29s destroyed two of the three hydrogen plants needed by the project. Despite the initial high hopes of their designers, the Japanese fire balloon campaign was totally ineffective and survives in memory only as an ingenious curiosity.
Right: A Japanese fire balloon of mulberry paper (“washi”) re-inflated at Moffett Field, California, after it had been shot down by a U.S. Navy plane on January 10, 1945. The balloon is now owned by the National Air and Space Museum. Fire balloon envelopes and apparatus were found on the West Coast (Alaska, Washington, Oregon, and California); in the Mountain states (Arizona, Nevada, Idaho, Montana, Utah, Wyoming, and Colorado); and in the Midwest (Texas, Kansas, Nebraska, North and South Dakota, Michigan, and Iowa). A few balloons landed in Mexico and Canada (Manitoba, Alberta, Saskatchewan, Northwest Territories, and the Yukon).
Left: Japanese fire balloons shot down by a Lockheed P‑38 Lightning near Attu in the Alaskan Aleutian Islands captured on gun cameras, April 11, 1945. Fire balloons flew very high and surprisingly fast, and U.S. aircraft destroyed fewer than 20. Between 285 and 300 fire balloons reportedly landed in the U.S. The last one found was in Alaska in 1955, its payload still lethal after 10 years. Japanese wartime propaganda announced fire balloons had wreaked havoc to forests, cities, and farmland, inflicted casualties as high as 10,000, and described an American public in panic. The truth was, the six people killed in Oregon (one woman and five children) were the only casualties caused by Japan’s fire balloon campaign.
Right: The Japanese performed a small number of non-balloon attacks on the U.S. mainland throughout the war. In February 1942 Japanese submarine I-17 shelled an oil field up the beach from Santa Barbara, California, and damaged a pump house. Later that June submarine I-25 shelled a coastal fort, Fort Stevens in Oregon, churning up a swamp and a baseball field (photo shows soldiers inspecting the shell crater), and in September I-25’s crew assembled and launched a small float plane that dropped incendiary bombs, starting a few small forest fires.
Japanese Fire Balloons Land in U.S. and Canada, November 1944 to April 1945