Yaak, Montana, [ILLEGIBLE]Date unknown

# Yaak, Montana UFO Sighting, September 1, 1952

On the early morning of September 1, 1952, two airmen stationed at the 630th Aircraft Control and Warning Squadron near Yaak, Montana, observed colored lights moving in the sky southeast of their radar station. At the same time and place, their radar equipment picked up unidentified targets on the scope. The sighting lasted about an hour, from roughly 11:05 a.m. to 12:05 p.m. Zulu time (which corresponds to the early morning hours locally).

The lights started out red, green, or blue, then turned a yellowish-white color and remained that way for the last thirty minutes of the observation. No more than two lights appeared at any single moment. They moved in an erratic pattern within a small area, sometimes appearing to dive with a white vapor trail behind them, and sometimes remaining motionless. The lights seemed smaller and dimmer than stars. One light went out and turned into a black silhouette against the dawn sky. The observers heard no sound from the objects.

Three airmen watched the radar scopes and observed targets that corresponded to the visual sightings. The targets appeared as small permanent objects on the radar display. They would remain in one spot for a few minutes, disappear, and then reappear a few miles away. The radar estimated the objects were 50 to 80 miles away, though their altitude could not be measured. The radar operator determined the objects were moving at extraordinarily high speeds, possibly around 1,200 miles per hour, though he could not be certain they were the same target across multiple radar returns. A weather analysis detected a mild temperature inversion (a layer in the atmosphere where temperature rises instead of falling with altitude), which can sometimes cause radar targets from ground objects to appear on radar screens.

The U.S. Air Force concluded that the radar targets were probably ground objects detected by the inversion condition, according to the official analysis in the file. The visual observations were treated as unknown. No interception was attempted because no fighter aircraft were available. The file includes 37 pages of supporting documents, including detailed witness statements, radar logs, weather data, and atmospheric diagrams held by the National Archives.