Balloon Bombs

Photographs of balloon bombs

U.S. Air Force

Balloon bombs were a Japanese innovation. When the Japanese found themselves unable to retaliate by any conventional means against the U.S. strategic bombing campaign of 1944, the Noborito Reasearch Institute developed designs for large (13' or 4 meter) hydrogen-filled balloons armed with incendiary and antipersonnel bombs. The balloon bombs were equipped with automatic mechanisms to release ballast or hydrogen in order to maintain altitude within the jet stream. The jet stream would carry the balloons to North America within a matter of days, and a timing mechanism would then release the bomb load. The Japanese hoped to start large forest fires in the Pacific Northwest and spread panic among the civilian population.

According to Sears (2008), the balloon bomb program was known as Flying Elephant and was seen as a way for ordinary Japanese to share in the spirit of the kamikazes. Each balloon required the assembly of 600 strips of rice paper using paste, and the work was often done by schoolgirls or sex workers supervised by paperhangers. The first balloon bombs were launched in November 1944. The principal American response was to impose a press blackout to prevent the Japanese gaining any information on the effectiveness of the bombs. Hearing of no reports of the weapons, the Japanese concluded that the weapons had been ineffective and ended the balloon bombing campaign six months later. In fact, of the 9300 bombs released, remains of 285 were eventually discovered, and it is estimated that about 1000 reached North America. One bomb made it as far as the suburbs of Detroit. However, the only damage or casualties inflicted by the bombs were the deaths of a pastor's wife and five children who discovered a balloon bomb while on a picnic in Oregon. Because the balloons relied on the jet stream, which lies above the storm track, it was almost guaranteed that the balloon bombs would drop only on forest that was soaked by rain.

American officials were concerned about the possibility that the Japanese would arm the bombs with biological agents and quietly took precautions, such as distributing disinfectant to decontaminate balloon bomb wreckage. A number of fighters were assigned to air defense against the balloons and succeeded in shooting down about 20 of the weapons.

Ironically, this attempt to burn out the cities of the Pacific Northwest preceded by two or three months the first of the much more successful American fire bombing raids against Japanese urban areas.


Mercado (2002)

Sears (2008)

U.S. Air Force (2010; accessed 2010-12-1)

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