Elsie Mitchell had baked a chocolate cake for the picnic that day on May 5, 1945. The young pastor’s wife, five months pregnant with her first child, accompanied her husband and five children from their congregation as they set off for a sunny day of eating and fishing on Gearhart Mountain near Bly, Oregon.

As the Reverend Archie Mitchell parked and unloaded the car that morning, the children raced off toward Leonard Creek, Elsie trailing behind them. One of the children noticed a large, mysterious, gray object near the water. She called to Elsie and the other children, who soon gathered around. A child went to pick up the object — and a massive explosion shook the forest.

Elsie Mitchell became the only adult victim of an enemy attack on the U.S. mainland during World War II. All five children also perished. The cause was Japanese balloon bombs, also known as fu-go. Made of mulberry paper and filled with hydrogen, these balloons were set aloft in the jet stream of the Pacific toward the end of the war, between November 1944 and April 1945. Each balloon carried multiple bombs, designed to kill, start forest fires, and sow panic.

Although there had been earlier sightings of the balloon bombs, the U.S. government asked the media not to report on them in order to avoid panic and to persuade the Japanese that their efforts had been fruitless. The latter strategy worked: Japan had actually canceled the program a month before the Oregon deaths, convinced their program had failed. Of course, by then, hundreds, if not thousands, of the balloons had made it to the mainland. 

When the Mitchell party tragedy was announced in the local media, no precise cause of death was given. U.S. officials didn’t fully lift the information blackout on the bombs until the following month, when it became evident that the public needed to be warned. All told, 361 balloon bombs were eventually found in the U.S., Canada, and Mexico, and while some did explode, the damage was minimal. (They never did start any forest fires — apparently the Japanese underestimated just how rainy the forests of the Pacific Northwest actually are.) Today, a stone-and-bronze monument marks the spot, about 13 miles northeast of Bly, where the only mainland deaths of World War II occurred.