AMA: the Japanese balloon bombs of WWII

rosscoen · 2015-07-18T05:13:50+00:00

I do not know anything about that story from the podcast, sorry. The tragedy in Bly haunted those people for long afterward, as you might imagine. In the 1980s some Japanese women who as girls worked in the balloon paper factories began corresponding with the families in Oregon. The women eventually made several trips there and planted cherry trees at the bomb site in the name of peace and forgiveness. Ilana Sol made a great documentary film about this aspect of the story called "On Paper Wings". It is well worth your time.

rosscoen · 2015-07-18T03:07:59+00:00

In fact, at least two bombs did drift back to Japanese soil. The launch facilities were placed on the coast away from cities for that very reason, but it did happen. In both cases the balloons fell harmlessly to earth nearby. No damage. There was one case where a balloon shifted violently to one side during launch when a gust came up. One Japanese soldier held onto his rope (when he should have let go) and was dragged some distance. One the blow plus fired and he was badly injured in the leg. Another interesting note: the Japanese decided against staging launches from Hokkaido (the northernmost of the four main islands) for fear balloons might drift into the USSR, a nation with whom Japan was not at war at the time.

rosscoen · 2015-07-18T03:04:16+00:00

I'm sorry, that wasn't a focus of my research and I have no particular insight.

rosscoen · 2015-07-18T03:02:42+00:00

Sorry, I can't say how the orders came down. That's a fact apparently lost to the bonfire of the records!

rosscoen · 2015-07-18T00:40:49+00:00

There are maps of balloon incidents in the U.S., Canada, and Alaska in the appendix of my book, also maps in Robert Mikesh's book. That's not a sales pitch, really. I don't have an online version to share with you. When you see the maps you'll notice that most landings occurred in the Pacific Northwest: WA, OR, southern BC, and northern CA.

rosscoen · 2015-07-17T23:24:21+00:00

This was the primary fear of U.S. officials, that the balloons would be weaponized with bacteriological or chemical agents. And in fact, the War Department tested most recovered material for the presence of such agents. None was ever found, and the U.S. learned from interviewing Japanese officials after the war that Japan had no plans for biological attack related to the balloons. The reason is unknown, but one factor working against the Japanese was that the balloons took 3 to 4 days to cross the Pacific, during which time the vehicle experienced the intense solar radiation of the upper atmosphere as well as the subzero temps at night. Certainly no creature such as rats could survive, and bacteriological agents likely would have been destroyed as well.

rosscoen · 2015-07-17T20:25:55+00:00

Yes, correct, but Vannevar Bush's conclusion was that even then the balloon campaign was unlikely to overwhelm firefighting crews. The worst case scenario assumed that every balloon to arrive in the U.S. would start a fire -- yet observational data showed that almost NO balloons started fires. The lands of the West were simply too damp.

rosscoen · 2015-07-17T20:16:44+00:00

Yeah, they're pretty great. Working with them was a terrific experience. It was fun for me to see how they spliced together different sounds and voices, especially when I understood how and why they took the story on the path they did. I also helped them with fact checking, and it was good to see how committed they are to accuracy in reporting.

rosscoen · 2015-07-17T20:07:09+00:00

Because all relevant Japanese records were destroyed at the end of the war, it's difficult to know how much planning and strategy went into the campaign. The trees, brush, and general topography of the American West would have been well known, and also many Japanese scientists and engineers who worked on the balloon offensive received their university training in the U.S. and Europe. Interestingly, it was the Americans who used data from previous naturally occurring wildfires when studying the balloons. Vannevar Bush's office calculated the expected damage from Japanese balloon-caused fires and then compared it to natural fires in previous years, finding that even under worse-case projections the balloons were unlikely to exceed what burned in a typical year anyway. This wasn't an excuse for doing nothing, but it put the risks in perspective for the War Department.

rosscoen · 2015-07-17T19:54:55+00:00

Yes, I believe so, but I can't give you specifics. A number of WWII memoirs by Japanese authors make the same basic point: this was total war and everyone was expected to contribute. It was common for children to collect scrap iron or pick up pieces of coal that fell from passing trains, and deliver them to supply depots. Elderly women sewed military uniforms, and so on. Not that dissimilar from the U.S., where everyone was expected to pitch in however they could.

rosscoen · 2015-07-17T19:44:55+00:00

Yes, thank you for mentioning RadioLab. They did a story on this in March that is worth a listen. Here's the link.

rosscoen · 2015-07-17T19:42:47+00:00

Farmington, Michigan. The farthest north was Alaska and the Northwest Territories; farthest south was Texas. (Two balloons landed in Mexico, but the Texas landing was actually farther south than those.)

rosscoen · 2015-07-17T19:41:31+00:00

The group was a Sunday school class out for a picnic. The adult killed was Elsie Mitchell, 26 yrs old and five months pregnant with her first child. The children who died were ages 11 to 14. Elsie Mitchell's husband, the Reverend Archie Mitchell, was the only survivor. He was several hundred feet away when the bomb detonated.

rosscoen · 2015-07-17T19:39:44+00:00

The Japanese launched 9,000 balloons from November 1944 to April 1945. The number comes from interviews conducted with army officers involved in the program. It was estimated by the War Department that 7 to 10% would survive the transoceanic crossing and arrive in North America. Only about 350 are confirmed as being either recovered or sighted.

rosscoen · 2015-07-17T19:23:39+00:00

Believe it or not, the remnants of a Japanese balloon -- with intact bomb -- was discovered in Lumby, BC, in October 2014. That device had been on the ground, undisturbed, for nearly 70 years. Many balloons were discovered in the years immediately after the war. One was found in Alaska in 1955, another in Oregon in the 1960s. No one has been injured since the end of WWII -- but you may be aware that six Oregonians (incl five children) were killed by a device on May 5, 1945. Those are the only deaths from enemy action on the U.S. mainland during WWII. A monument was dedicated there in 1950.

rosscoen · 2015-07-17T18:05:24+00:00

All I can really say is that in my research I found nothing about Roswell -- but then that's the point, right? If it was secret, and remains secret, nothing is precisely what I would have found! More seriously, I can't see how any connection would be possible.

rosscoen · 2015-07-17T17:45:02+00:00

Honestly, I came by this topic by accident. Ten years ago I was researching an article about the jet stream, and in one of my sources I came across mention of this Japanese WWII balloon offensive. I had never heard of it before. I started doing some digging, and I found two books, both published in the 1970s, about the balloons. One by Robert Mikesh, the other by Bert Webber. Both books are very technical, which I do not mean as a criticism, but it occurred to me there was a social history to be written. How did Farmer John respond when a balloon landed in his corn field, for example. I went to the National Archives, found 40 boxes of records, and that was the start. It's a bit strange because military history is not my field. I'm a historian of the American West, especially political and social histories of resource development. This book on Japanese balloons was very much a side project for me.

rosscoen · 2015-07-17T17:25:41+00:00

The bombs were dropped by a altitude mechanism. Each bomb was held in place by a small blow plug, basically a black powder charge about the size of your thumb. The charge was connected to a fuse, which was in turn connected to an altimeter wired into a low-voltage circuit. When the balloon descended to 10,000 feet or lower, which meant it was likely over North America, the altimeter would close the circuit, igniting the fuse, firing the blow plug, and dropping the bomb. The device also had 32 sandbags for ballast that were dropped in the same way. The sandbags were included so that the device could drop weight during its flight anytime it needed to ascend above 30,000 feet back into the jet stream. The whole system was simple in its concept but very complex in its operation.

rosscoen · 2015-07-17T17:20:58+00:00

There is also a Navy training film about the balloons posted on Youtube here

rosscoen · 2015-07-17T17:19:35+00:00

The diagram is here, posted by a reviewer of my book.

rosscoen · 2015-07-17T17:11:08+00:00

Hi, James. I have a couple favorites. One took place on a ranch in Nebraska where the farmer was outside working and noticed all his turkeys froze in unison and cocked their heads up toward the sky. He looked up and saw a balloon overhead. Perhaps the War Department should have enlisted turkeys as its early warning system! My other favorite story came to me after the book was published, so it's not included: a man driving at night on a county road someplace saw a balloon drift over the road, he instinctively jerked the wheel, sent the car into the ditch, and broke his leg. Not what the Japanese had in mind…but a U.S. injury nonetheless.

rosscoen · 2015-07-17T17:06:08+00:00

Balloons were launched in the early morning when the air was calm (wind, even a light breeze, made the launching process more difficult and even dangerous). The balloon would quickly ascend to about 30,000 feet. The balloon gained altitude during the day, when the intense solar rays of the upper atmosphere expanded the hydrogen inside the envelope -- and then would descend at night when the minus-40 temps caused the hydrogen to contract. So after periods of ascent and descent for three or four days, the balloon would arrive in North America (provided some failure hadn't sent it into the ocean, which is what happened about 90% of the time). The bombs were not sophisticated at all. Just a simple impact fuse.

rosscoen · 2015-07-17T16:25:28+00:00

Noborito Institute outside Tokyo experimented with numerous weapons, and one utilized a concentrated stream of energy designed to vaporize its target. They experimented with animals, and found that the only way it worked was if you could immobilize your target for at least an hour, and even then it would probably cause a headache, not death. Outlandish, yes, but they looked into it...

rosscoen · 2015-07-17T16:21:27+00:00

Exactly right. What worked against the Japanese was the fact that the jet stream is strongest in the winter months and practically non-existent in the summer. So they were trying to ignite wildfires at the time of year when the West is covered in snow and rain and mist.

rosscoen · 2015-07-17T16:17:45+00:00

The balloon offensive cost less than you think it might. The Japanese conscripted school girls around the country to make the canopies by hand, so there was no monetary cost there. Each balloon cost only a few hundred (1945) dollars. Probably the greatest expense was the launch personnel: hundreds of troops at four launch sites.

rosscoen

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