CASS LAKE, Minn. — There would have been no way for the small church group to know the day they set out for a picnic in Oregon in 1945 would be their last. And yet, most of the people in that group, which included two teenagers from Cass Lake, would go down in history as the only civilians killed from foreign weapons in the continental United States during World War II.

They were killed when they stumbled upon an unusual device known as a Japanese balloon bomb that exploded once they began looking at it.

Betty Patzke, who was a sibling to two of the youths from Cass Lake who died, went onto marry Archie Mitchell, whose wife was another of the victims who died in the explosion. And while both Mitchell and Patzke lost loved ones that day during the outing in Oregon, the tragedy also helped shape their future together and the work they would be involved in. Their legacy is set to be recognized at a community gathering this weekend in Cass Lake.

“That was impactful for her because her brother (Dick) and sister (Joan) were killed; she wasn’t ever thinking about going overseas at that point,” Becki Thompson said about how the bomb blast affected her mother, Betty Patzke Mitchell. “It was her younger sister who was killed who was going to do that.”

Thompson is one of the speakers set to appear at the Cass Lake Alliance Church’s “Homecoming Weekend Celebration,” where she will continue to expound on her mother, as well, as how the incident impacted her life from that point on.

Betty’s family was a part of the small church in Cass Lake before they moved out to the Pacific Northwest. Although it wasn’t her original plan to go overseas, Betty Patzke would go on to serve in Asia. Archie Mitchell, her husband, would go missing during their time in Vietnam.

Betty’s daughter, Becki Thompson, would go on to serve nearly four decades in Africa with her husband David.

“(They) have this amazing history and story” Smith said of Becki and David Thompson. “When your trace it all back, it all comes back to our little home church here in Cass Lake. Our church has always been a small church, but it’s collective history is amazing.”

And, in one way or another, the legacy that Betty would have on the world can also be traced back to that fateful day when the members of that church group noticed something odd-looking in the Oregon woods.

As the story goes, the youth were going on a picnic in Bly, Ore., on May 5, 1945. As they were arriving at the location, one of the adults and multiple youth were exploring when they stumbled across what turned out to be a Japanese balloon bomb.

The archive section of the Oregon Secretary of State said Archie Mitchell was parking the car when his pregnant wife, Elsye, called out to him that she and the youth found something peculiar.

“Look what I found, dear,” Elsye shouted to Mitchell, according to the archives. One of the youth tried to dislodge the balloon bomb from the tree, and it triggered the device, the archives said.

The explosion killed Elsye Mitchell, as well as five youth — Dick Patzke, 14; Jay Gifford, 13; Edward Engen, 13; Joan Patzke, 13 and Sherman Shoemaker, 11.

The Mitchell Monument now stands at the site of the tragedy in Klamath County, Ore.

According to the Smithsonian, they were the only civilians to die from “enemy weapons” in the continental United States during World War II.

The U.S. Forest Service said balloon bombs were known as “Fugos,” or wind ships, and were meant to traverse the ocean and explode over the United States, causing forest fires and wreaking havoc. Japan reportedly launched more than 9,000 such balloons, resulting in more than 300 incidents in both the United States and Canada.

Flying high on jet streams, the concept of the bomb was not all that different from a hot air balloon that innocent picnickers likely would think nothing more of if they saw it sailing across the sky today. A series of suspension lines would hang the explosive device under the balloon itself until it eventually reached its destination.

Unlike the modern hot air balloons, though, those created during the war had far more severe consequences, at least for the small group in Oregon on that day in 1945.

The Smithsonian Magazine wrote an article about the odd tragedy in May. In that piece, they hinted at some of Betty’s thoughts that impacted her from that day.

“When you talk about something like that, as bad as it seems when that happened and everything, I look at my four children, they never would have been, and I’m so thankful for all four of my children and my ten grandchildren. They wouldn’t have been if that tragedy hadn’t happened,” the Smithsonian quoted Betty as telling the filmmaker Ilana Sol.