St. Croix Falls, WisconsinOctober 1951

# UFO Sighting Near St. Croix Falls, Wisconsin

On October 10, 1951, two experienced balloon researchers saw an unusual object while tracking a weather balloon near St. Croix Falls, Wisconsin. J.J. Kaliszewski and Jack Donachus were flying in an aircraft at 6,000 feet when they spotted something strange crossing the sky far above them, moving from east to west. Using their balloon, which they estimated was at about 20,000 feet, they judged the object to be roughly one-quarter the size of the balloon.

The object had a peculiar glow and moved very rapidly across the sky. It first descended slightly, then leveled off and slowed down before making a sharp left turn and climbing at a steep angle of 50 to 60 degrees toward the southeast. The climb happened with what Kaliszewski described as "terrific acceleration." The entire sighting lasted about two minutes, and the object covered an arc of roughly 40 to 50 degrees across the sky. Neither observer saw a vapor trail.

Kaliszewski and Donachus were confident about what they had not seen. In Kaliszewski's own words: "I know that this object was not a balloon, jet, conventional aircraft, or celestial star." Shortly after this sighting, a second similar object appeared, approaching from the west and disappearing to the east just as quickly.

When Kaliszewski reported the sighting by radio to a General Mills tracking station on the ground, two crew members there, Doug Smith and Richard Dorian, used a theodolite (a telescope-like surveying instrument) to try to track the objects, though they could only catch brief glimpses. The Air Force evaluated the case as "unknown," finding no conventional explanation for what the trained observers had described.

The full case file, including witness statements, official reports, and contemporary newspaper coverage, is reproduced below as held by the National Archives in 11 pages of microfilm.