On This Day: 6 fatalities from Axis action in continental U.S. during WW2 - May 5, 1944

(edited from Wikipedia)
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Fu-Go Balloon Bomb

Fu-Go was an incendiary balloon weapon deployed by Japan against the United States during World War II. It consisted of a hydrogen-filled paper balloon 33 feet in diameter, with a payload of four 11-pound incendiary devices and one 33-pound high-explosive anti-personnel bomb. The uncontrolled balloons were carried over the Pacific Ocean from Japan to North America by fast, high-altitude air currents, today known as the jet stream, and used a sophisticated sandbag ballast system to maintain their altitude. The bombs were intended to ignite large-scale forest fires and spread panic.

[About 300 cross the ocean]

Between November 1944 and April 1945, the Imperial Japanese Army launched about 9,300 balloons from sites on coastal Honshu, of which about 300 were found or observed in the U.S., Canada, and Mexico. The bombs were ineffective as fire starters due to damp seasonal conditions, with no forest fires being attributed to the offensive.

[Six civilians killed in Oregon]

A U.S. media censorship campaign prevented the Imperial Army from learning of the offensive's results. On May 5, 1945, six civilians were killed by one of the bombs near Bly, Oregon, becoming the war's only fatalities in the continental U.S. The Fu-Go balloon bomb was the first weapon system with intercontinental range, predating the intercontinental ballistic missile.

[How the balloons made it so far]

Changing pressure levels in a fixed-volume balloon posed technical challenges. During the day, heat from the sun increased pressure, risking the balloon rising above the air currents or bursting. A relief valve was added to allow gas to escape when the envelope's internal pressure rose above a set level. At night, cool temperatures risked the balloon falling below the currents, an issue that worsened as gas was released. To resolve this, engineers developed a sophisticated ballast system with 32 sandbags mounted around a cast aluminum wheel, with each sandbag connected to gunpowder blowout plugs.

The plugs were connected to three redundant aneroid barometers calibrated for an altitude between 25,000 and 27,000 feet, below which one sandbag was released; the next plug was armed two minutes after the previous plug was blown. A separate altimeter set between 13,000 and 20,000 feet controlled the later release of the bombs. A one-hour activating fuse for the altimeters was ignited at launch, allowing the balloon time to ascend above these two thresholds.

A self-destruct system was added; a three-minute fuse triggered by the release of the last bomb would detonate a block of picric acid and destroy the carriage, followed by an 82-minute fuse that would ignite the hydrogen and destroy the envelope.

Offensive

A balloon launch organization of three battalions was formed. The first battalion included headquarters and three squadrons, totaling 1,500 men, at nine launch stations at Otsu in Ibaraki Prefecture. The second battalion of 700 men in three squadrons operated six launch stations at Ichinomiya, Chiba, and the third battalion of 600 men in two squadrons operated six launch stations at Nakoso, Fukushima. The Otsu site featured its own hydrogen plant, while the second and third battalions used hydrogen gas transported from factories around Tokyo. The combined launching capacity of the sites was about 200 balloons per day, with 15,000 launches planned through March. The Army estimated that only 10 percent of the balloons would survive the journey across the Pacific Ocean.

The first balloons were launched on November 3, 1944. Two weeks after the discovery of the B-Type balloon off San Pedro, an A-Type balloon was found in the ocean off Kailua, Hawaii, on November 14. More were found near Thermopolis, Wyoming, on December 6 (with an explosion heard by witnesses, and a crater later located) and near Kalispell, Montana, on December 11, followed by finds near Marshall and Holy Cross, Alaska, and Estacada, Oregon, later in the month.

Authorities were placed on heightened alert, and forest rangers were ordered to report landings and recoveries. The balloons continued to be discovered across North America, with sightings and partial or full recoveries in Alaska, Arizona, California, Colorado, Hawaii, Idaho, Iowa, Kansas, Michigan (where an incendiary bomb was found at Farmington in the easternmost incident), Montana, Nebraska, Nevada, North Dakota, Oregon, South Dakota, Texas, Utah, Washington, and Wyoming; in Canada in Alberta, British Columbia, Manitoba, Saskatchewan, and the Northwest and Yukon Territories; in Mexico in Baja California Norte and Sonora; and at sea. By August 1945, the U.S. Army had recorded 285 balloon incidents.

[Wildfires defense]

Most U.S. defense plans were only fully implemented after the offensive ended in April 1945. In response to the threat of wildfires in the Pacific Northwest during the summer months, the Army's Western Defense Command (WDC), Fourth Air Force, and Ninth Service Command organized the "Firefly Project" with a number of Stinson L-5 Sentinel and Douglas C-47 Skytrain aircraft and 2,700 troops, including 200 paratroopers from the all-black 555th Parachute Infantry Battalion, who were deployed in 36 firefighting missions between May and October 1945.

The Army used the U.S. Forest Service as a proxy agency, unifying fire suppression communications between federal and state agencies and modernizing the service through an influx of military personnel, equipment, and tactics.

[Countermeasures for biological warfare]

In the WDC's "Lightning Project", health and agricultural officers, veterinarians, and 4-H clubs were instructed to report any new diseases of crops or livestock caused by potential biological warfare. Stocks of decontamination chemicals, ultimately unused, were shipped to key points in the western states. Although biological warfare had been a concern for months, the WDC's plan was not formalized and fully implemented until July 1945. A sub-section of the project, "Arrow", provided for rapid air transportation of all balloon remains to the Technical Air Intelligence Center laboratory in Washington, D.C., for biological analysis.[30] A U.S. investigation after the war concluded there had not been plans for chemical or biological payloads.

[Some balloons shot down]

Army Air Forces and Navy fighter planes were scrambled on several occasions to intercept balloons, but they had little success due to inaccurate sighting reports, bad weather, and the very high altitude at which they traveled. In all, only about 20 balloons were shot down by U.S. and Canadian pilots.

[Where did the balloons come from?]

Few American officials believed at first that the balloons could have come directly from Japan. Statistical analysis of valve serial numbers suggested that tens of thousands of balloons had been produced. The mineral and diatom composition of sand from the sandbags was studied by the Military Geology Unit of the United States Geological Survey, which assessed its origin as Shiogama, Miyagi, or less likely, Ichinomiya, Chiba, only the latter being correct.

Censorship campaign

On January 4, 1945, the U.S. Office of Censorship sent a confidential memo to newspaper editors and radio broadcasters asking that they give no publicity to balloon incidents; this proved highly effective, with the agency sending another memo three months later stating that cooperation had been "excellent" and that "there is no question that your refusal to publish or broadcast information about these balloons has baffled the Japanese, annoyed and hindered them, and has been an important contribution to security."

Starting in mid-February 1945, Japanese propaganda broadcasts falsely announced numerous fires and a panicked American public, further claiming casualties in the hundreds or thousands.

One breach occurred in late February, when Representative Arthur L. Miller mentioned the balloons in a weekly column he sent to all 91 newspapers in his Nebraska district. In response, intelligence officers at the Seventh Service Command in Omaha contacted the editors at all 91 papers, requesting censorship; this was largely successful.

In late March, the United Press (UP) wrote a detailed article on the balloons intended for its national distributors. Censors contacted the UP, which replied that the article had not yet been teletyped; all five copies were retrieved and destroyed. Investigators determined the information originated from a briefing to Colorado state legislators, which had been leaked in an open session.

In [two] cases, the Office of Censorship deemed it unnecessary to censor the Sunday comics, [which depicted balloon attacks].

[Widespread fires don't happen]

As predicted by Imperial Army officials, the winter and spring launch dates had limited the chances of the incendiaries starting fires due to the high levels of precipitation in the Pacific Northwest; forests were generally snow-covered or too damp to catch fire easily. Furthermore, much of the western U.S. received disproportionately more precipitation in 1945 than in any other year in the decade, with some areas receiving 4 to 10 inches of precipitation more than other years.

[Irony - site of plutonium used for Nagasaki]

The most damaging attack occurred on March 10, 1945, when a balloon descended near Toppenish, Washington, and collided with electric transmission lines, causing a short circuit which cut off power to the Manhattan Project's production facility at the state's Hanford Engineer Works. Backup devices restored power to the site, but it took three days for its plutonium-producing nuclear reactors to be restored to full capacity; the plutonium was later used in Fat Man, the atomic bomb dropped on Nagasaki.

Single lethal attack

On May 5, 1945, six civilians were killed near Bly, Oregon, when they discovered one of the balloon bombs in Fremont National Forest, becoming the only fatalities from Axis action in the continental U.S. during the war. Reverend Archie Mitchell and his pregnant wife Elsie (age 26) drove up Gearhart Mountain that day with five of their Sunday school students for a picnic. While Archie was parking the car, Elsie and the children discovered a balloon and carriage, loaded with an anti-personnel bomb, on the ground. A large explosion occurred; the four boys were killed instantly, while Elsie and Joan Patzke died from their wounds shortly afterwards. An Army investigation concluded that the bomb had likely been kicked or dropped, and that it had lain undisturbed for about one month before the incident. The U.S. press blackout was lifted on May 22 so the public could be warned of the balloon threat.

In 1987, a group of Japanese women involved in Fu-Go production as schoolgirls delivered 1,000 paper cranes to the victims' families as a symbol of peace and healing, and six cherry trees were planted at the site on the incident's 50th anniversary in 1995.

[Remains of balloons, live bomb, continued to be discovered - 2014 and 2019]

The remains of balloons have continued to be discovered after the war. At least eight were found in the 1940s, three in the 1950s, two in the 1960s, and one in the 1970s. A carriage with a live bomb was found near Lumby, British Columbia, in 2014 and detonated by a Royal Canadian Navy ordnance disposal team.

Remains of another balloon were found near McBride, British Columbia, in 2019. Many war museums in the U.S. and Canada hold Fu-Go fragments, including the National Air and Space Museum and Canadian War Museum.
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https://en.wikipedia.org/wiki/Fu-Go_balloon_bomb

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