Pacific Northwest, Washington and Oregon States, May 1953May 1953

# Summary: Unknown Radar Tracks, Pacific Northwest, May 1953

On May 13, 1953, radar operators at two U.S. Air Force stations in the Pacific Northwest detected unidentified objects moving over Washington and Oregon. The Air Force scrambled fighter aircraft to intercept them, but pilots could not locate the targets visually. The radar blips appeared consistent with solid, airborne objects, yet the aircraft searches turned up nothing.

The first radar target, labeled B-97-G, appeared on scope at 0415 hours (4:15 a.m.) in the Pacific ADIZ (Air Defense Identification Zone). It maintained an altitude of 6,000 feet and traveled at approximately 90 knots ground speed. A second target, B-14-G, appeared later at 0456 hours and flew at a similar altitude and 80 knots speed. The Air Force dispatched four fighter-interceptors to investigate. Two aircraft pursuing the first target, callsigns Pronto Red and Sixpence White, reported getting radar lock-on multiple times but could never establish visual contact. The pilots noted the targets seemed to lack their own forward motion, requiring constant overtake speed to pursue. One pilot suggested the radar contacts resembled chaff (radar reflective material dropped for countermeasures). Similarly, aircraft vectored to intercept the second target also failed to find anything visually.

Investigators examined several possible explanations. A weather balloon released from Tillamook, Oregon, on May 13 was tracked and accounted for. Weak radio transmissions on 500 kilocycles were received by a Coast Guard operator at Westport, Washington, possibly indicating multiple transmitters using homing techniques for rendezvous. Importantly, researchers discovered a temperature inversion (a layer of warm air trapping cooler air below) between 1,500 and 1,700 feet above sea level that morning. Specialists from the USAF Research and Development Command and the University of Texas confirmed that inversions could produce unusual radar phenomena, including false blips on radar scopes and null zones where targets disappear. This atmospheric condition may have explained why one nearby radar station could not paint the targets while another station received strong returns.

The report concluded that no firm identification of the targets could be reached. The Air Force evaluation remained "unknown."

The full case file is reproduced below as held by the National Archives, consisting of 13 pages.