Section: ARMAMENT

ON WEDNESDAY, DECEMBER 6, 1944, four people at a coal mine near Thermopolis, Wyoming, reported seeing, according to a local newspaper, "a parachute in the air, with lighted flares and after hearing a whistling noise, heard an explosion and saw smoke in a draw near the mine at about 6:15 p.m." A search the next day turned up a piece of paperlike material and fragments from a heavy bomb. It was believed that the material was from the parachute of a landing flare and that the bomb was from an airplane, although no plane had been reported in the area, nor was one listed as missing.

Five days later two woodcutters reported finding a parachute in the mountains some 17 miles southwest of Kalispell, Mont. An investigation by local sheriffs determined that the object was not a parachute, but a large paper balloon with ropes attached along with a gas relief valve, a long fuse connected to a small incendiary bomb, and a thick rubber cord. The balloon and parts were taken to Butte, where personnel from the FBI, Army and Navy carefully examined everything. The officials determined that the balloon was of Japanese origin, but how it had gotten to Montana and where it came from was a mystery.

These two incidents were not the first of their kind to be reported. The first had occurred on November 4, 1944, when a U.S. Navy craft patrolling the waters 66 miles southwest of San Pedro, Calif., recovered a rubberized balloon carrying a small radio transmitter from the ocean. At the time, the Navy believed it was a weather balloon and dismissed it. Within the next 10 days, another such balloon that had been found back in August on a ranch near Yerington, Nev., came to light, and the fragments of another paper balloon were recovered just off the coast of Kailua, Hawaii.

As the number of incidents increased, it became evident that all the balloons were of Japanese manufacture, and the government began an all-out investigation. According to Brig. Gen. W.H. Wilbur, chief of staff of the Western Defense Command during the war: "From the first we realized the possibilities of this new campaign. Hence the assistance of all government Agencies--national, state and local--was immediately enlisted. The Navy was alerted and the FBI was called in. Forest rangers, state and national, were informed that we wanted reports of balloon landings and any portion of balloons or undercarriages that were recovered."

As soon as the balloons and parts were recovered, they were sent to the Naval Research Laboratory in Washington, D.C., for analysis. The rubberized balloons were found to be weather balloons, as the Navy had originally thought. However, the paper balloons turned out to be something completely different. On January 18, 1945, the Naval Research Laboratory announced: "It is now presumable that the Japanese have succeeded in designing a balloon...which is capable of reaching the United States and Canada from the western Pacific carrying incendiaries and other devices .... It must be assumed that a considerable number are coming over."

The announcement was correct--the Japanese had embarked on a campaign to bring the war home to America. Although Lt. Col. Jimmy Doolittle's bombing raid over Japan on April 18, 1942, had done little damage, it had come as a great psychological blow to the Japanese people and humiliated the military. In response, the Japanese had made the decision to strike at the American mainland. At the time, the Japanese were working on a project for using small, ship-launched balloons to interfere with American planes taking off from the airfields on Guadalcanal. When the battle there turned against the emperor's forces, and the balloons could not be used, the Japanese decided to redesign them for an assault on North America. The new balloon project, dubbed Fugo (windship weapon), called for sending bomb-carrying balloons from Japan to set fire to the vast forests of America, in particular those of the Pacific Northwest. It was hoped that the fires would create havoc, dampen American morale and disrupt the U.S. war effort.

The first obstacle the project faced was how to get the balloons across more than 6,000 miles of ocean. For the Japanese, this was not as major an obstacle as it appeared. They planned to use the jet stream, the meandering current of high-velocity air traveling west to east, miles above the earth's surface, to propel the balloons across the Pacific. By using the jet stream to carry the balloons from Japan to North America, the Japanese had developed the world's first intercontinental weapon.

The Japanese created two types of balloons, one made by the army and the other by the navy. The first to go into operation were the Imperial Navy's "Type B" balloons. Type B balloons were 9 meters (29.5 feet) in diameter and made of rubberized silk. They were used for meteorological studies to determine the feasibility of sending unguided, bombladen balloons to North America, and only 300 were built. This was the type of balloon found on November 4, 1944, off California and that August in Nevada.

The army balloons, dubbed "Type A," were used to bomb North America. Those balloons, or balloon bombs as they are more commonly called, were an ingenious idea, mating the simplicity of a lighter-than-air balloon with the sophistication of altitude sensors and release devices for bombs and ballast bags. They consisted of a 10-meter (32.8-foot) diameter hydrogen-filled balloon, or envelope, fabricated from panels made up of three or four layers of laminated tissue paper. The tissue paper came from the bark of the koso and the matsumata trees and made a light but durable envelope. After the balloon was assembled, it was given a lacquerlike coating to make it weatherproof. Although light in weight, which made it easy to launch, it could lift 1,000 pounds at sea level and about 300 pounds at 30,000 feet. Attached to the balloon, two-thirds down from the top, was a scalloped belt from which lines ran down to a heavy cord that was connected to the payload either directly or by means of a rubber shock absorber.

The base for the payload was a 321/2-inch diameter, four-spoke, cast aluminum ring, called the ballast ring. Positioned along the outer edge of this ring were 36 pairs of blow-plugs--small metal tubes packed with black powder, fired electrically. Suspended from the ring were four 5-kilogram (11-pound) incendiary bombs for starting forest fires, and up to 32 sand-filled ballast bags. Each of these was connected by a hook to a pair of blow-plugs and released when its blow-plugs were triggered by the balloon's firing system. Hanging from the center of the ting, and released by another set of blow-plugs, was a 15-kilogram (33-pound) high explosive anti-personnel bomb or a 12-kilogram (26-pound) incendiary bomb. The bombs were not armed until an "arming wire" was pulled from them as they dropped from the ballast ring. Above the ballast ring was a second, smaller ring that contained the trigger devices for the sequential firing system for the blow-plugs and supported two levels of mechanisms. These included the aneroid barometers for controlling the balloon's altitude, various electrical components, a wet-plate battery for power and a self-destruct device.

Upon launching, the balloons ascended quickly into the jet stream, where their altitude could vary drastically due to day and night changes in the temperature. To counter that, the Japanese developed a system to keep the balloons between 30,000 and 38,000 feet. Gas was released by a pressure-operated relief valve in the bottom of the envelopes, preventing the balloons from gaining too much altitude and possibly bursting when the gas inside heated up and expanded. To keep the balloons from descending too low when the gas contracted, aneroid barometers, which constantly monitored the balloons' altitude and were connected to the blow-plugs' firing system, released ballast bags as needed. Although the balloons' altitude still varied, they averaged around 30,000 feet as they hopped across the Pacific.

The Japanese calculated that by the time all the ballast bags had been dropped, the balloons would have reached North America. With all the ballast bags gone, the blow-plug firing system would begin releasing the bombs. One bomb was released every 24 hours, starting with the outer incendiaries and dropping the center-mounted bomb last. The spacing of the bombs supposedly allowed each balloon to start fires in several different locations, thus spreading destruction and panic over a wide area.

To add to the panic, the Japanese planned to make the balloons vanish when they finished their work by placing two self-destruct devices on each one. When the last bomb was dropped, the balloon's blow-plugs also ignited the fuses to those devices. One fuse set off an explosive charge in the balloon's payload, blowing it to pieces. The second, and much longer, fuse was connected to a package of magnesium flash powder attached to the side of the balloon envelope. About an hour after the payload was destroyed, that fuse ignited the flash powder, which burned through the envelope and set the hydrogen gas inside on fire. The only thing left of the balloon bomb would be fragments of its payload, and they would be scattered over a large area and would probably be unidentifiable. (For some reason, some balloons launched later in the campaign did not have a self-destruct device attached to the envelope.) The Japanese planned the balloon bombs to be a silent form of attack--in effect, a stealth weapon.

By the beginning of November 1944, the Japanese were ready to launch their balloons. The timing was good, since from November to March the jet stream was strong enough to carry the gas bags across the Pacific in three to four days. What the Japanese apparently did not take into account was that this was also the wettest time of the year for the forests and woodlands of North America, making the chances of setting fire to them virtually nil. The balloons were launched from 21 launching pads at three sites along the east coast of Japan's main island of Honshu. The first balloon was launched on November 3. The Japanese planned to continue the launchings through March, but due to weather delays they did not end until mid-April 1945.

In all, the Japanese planned to launch 10,000 to 15,000 balloons during this time period. Due to the destruction of Japanese records, however, the actual number of balloons launched is unknown. Of the approximately 10,000 built, it has been estimated that somewhere between 6,000 and 9,300 were actually launched. How many of those managed to cross the Pacific and reach North America is unknown. The estimates range from 300 to well into the thousands--we will probably never know. What is known is that the remains of some 200 balloons were found.

Since the Japanese were able to intercept American radio and newspaper reports, they expected to quickly learn of the balloons' effectiveness. And in the first two months of the campaign, a few reports of balloon incidents were carried by the press. However, in January, just as the balloons started to arrive over :North America in large numbers, that changed when the U.S. government asked the media to cease reporting on the balloons. The government made the request in order to stop the Japanese from finding out how successful they were and to prevent them from panicking the American people. The news media cooperated fully, and it was not until after the war that the Japanese learned the true results.

The only notable success the Japanese scored on the American war effort happened on March 10, 1945, in south-central Washington state. On a large tract of land along the west bank of the Columbia River, some 20 miles north of Richland, stood the Hanford Engineering Works. The well-guarded facility was no ordinary factory engaged in wartime work, but a top-secret government plant manufacturing plutonium for the equally top-secret Manhattan Project--the program for the development of the atomic bomb.

Just before 3:30 on that rainy afternoon, some 30 miles west of the plant, a Japanese balloon struck the main transmission line bringing power to Hanford from the Bonneville Dam. The balloon short-circuited the line, cutting off all power to Hanford. Although the power was only off for a split second before power from the Grand Coulee Dam switched in, it triggered the safety systems to Hanford's nuclear piles and shut them down. It took Hanford's personnel three days to get the piles back to full operation. It seems ironic that the interruption caused by .the Japanese balloon to the Manhattan Project was due not to the balloon's bombs but to the balloon itself. In keeping with the government's policy, the cause for the shutdown at Hanford was kept secret from all but a few of the operation's top officials.

Two months later, on May 5, 1945, the only fatalities resulting from the balloons occurred in Oregon. That morning, the Reverend Archie Mitchell and his pregnant wife Elsye packed their car with fishing gear and a picnic lunch. They were taking five children from the reverend's Sunday school on an outing to Gearhart Mountain, which was not far from their home in Bly, Ore. With the car loaded and Mrs. Mitchell and the children squeezed in, the minister set off that sunny May morning, anticipating a great day.

After an uncomfortable ride over a rough and muddy service road, they reached the planned site of their outing. While the reverend was parking the car, his wife and the children walked a few hundred yards into the woods to inspect a nearby creek for fishing. As they neared the creel Mrs. Mitchell and the children came across a strange-looking metal object lying on the ground. Mrs. Mitchell called to her husband that they had found something usual. The reverend called back to her to wait a moment, and he would come and look at it.

Suddenly, a loud explosion came from the area where Mrs. Mitchell and the children were standing, shattering the quiet of the forest. Richard Barnhouse, the foreman of a Forest Service crew working close by, reported, "As Mr. Mitchell stopped his car, there was a terrible explosion. Twigs flew through the air, pine needles began to fall, dead branches and dust and dead logs went up."

The reverend quickly ran to the site of the explosion closely followed by Barnhouse and his crew. Their eyes met a dreadful scene of devastation. Lying around a small crater were the mangled bodies of Mrs. Mitchell and the five children--all dead except Mrs. Mitchell, who died of her injuries soon after.

What Mrs. Mitchell and. the children had found was a 15-kilogram high-explosive anti-personnel bomb from a crashed Japanese balloon. Apparently someone touched or moved the bomb, and it went off. An inspection of the site later in the day by military personnel discovered the collapsed balloon, four unexploded bombs and an intact self-destruct device.

Because of the secrecy surrounding the balloons, the cause of the death of Mrs. Mitchell and the children was listed as being from "an explosion from an undetermined source." They were the only casualties due to enemy action on the U.S. mainland during the war.

According to Japanese propaganda, the balloons were a great success. They had started scores of fires, resulting in thousands of deaths and mass panic. That was not the case, however. Because the balloons were sent over in the winter when the forests were wet and frozen, the massive forest fires the Japanese envisioned did not materialize. In fact, no forest fires were ever verified as having been caused by the enemy balloons.

If the Japanese had gone ahead with their second balloon campaign, using larger balloons carrying more bombs and planned for the dry summer months of 1945, the results could have been very different. In all, the balloons caused only six deaths, and due to the news blackout most Americans did not even know about those.

Near the end of April 1945, the Japanese stopped all work on the Fugo project and canceled all further balloon launchings. Major General Sueki Kusaba, commanding general of the Fugo project, wrote: "Soon after the campaign began, the air raids against our mainland were intensified. Many factories which manufactured various parts were destroyed. Moreover, we were not informed about the effect of Fugo throughout the war. Due to the combination of hardships we were compelled to cease operations." It was the view of the Japanese general staff that if the balloons were reaching North America, "reports would be in the newspapers [as] Americans could not keep their mouths closed this long."

Although the Japanese balloons accomplished little, their legacy lives on. Since the end of the war more than a dozen balloon parts have been found and reported. Given the number of balloons that could have reached North America, authorities warn that hundreds of unexploded balloon bombs may still be lying in wait for the unsuspecting.

S (BLACK & WHITE): Developed in the wake of Lt. Col. Jimmy Doolittle's successful raid on Tokyo, the fragile Japanese balloon bombs were able to take advantage of the jet stream to reach targets in North America with their payloads of incendiary and anti-personnel bombs.

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By James M. Powles