Portland, OregonJune 1947

In June 1947, a Portland-area prospector reported seeing five or six disk-shaped objects banking and maneuvering in the sky while he worked in the Cascade Mountains near the Oregon-Washington border. The observer watched the objects through a telescope for several seconds. During the sighting, he noticed that the compass hand on his special watch was moving wildly from side to side.

The Air Force investigators noted that the observer had submitted his report after reading about another UFO sighting that occurred on the same day (Incident No. 17). This timing raised questions about whether the observer might have been influenced by the newspaper account. The investigator suspected the witness may have either consciously or unintentionally shaped his own report to match the details he had read.

The file included technical analysis of the compass disturbance. An Air Force scientist calculated that if the objects had actually produced the magnetic field the compass behavior suggested, they would have needed to generate enormous electromagnetic forces, far beyond what seemed physically plausible. The investigator concluded that such fantastically large magnetic fields made the compass effect difficult to take seriously.

The Air Force evaluation noted two psychological factors: first, the observer's admitted motivation to report his sighting only after reading about the earlier incident, and second, his emphasis on the magnetic compass effect, which he appeared not to fully understand. Based on the limited evidence and these considerations, the Air Force determined it could not reach a definite conclusion about what the objects were. The full case file is reproduced below as held by the National Archives, containing 10 pages.