44.15N 132.57W (Pacific), August 1949August 1949

On August 2, 1949, the crew of a U.S. Air Force weather plane spotted an unusual cloud formation over the Pacific Ocean about 400 miles west of Eureka, California. Three officers saw what appeared to be white streaks of clouds or contrails forming an ascending pattern. The formation started near some low clouds at about 1,500 feet, climbed at a steep angle to roughly 15,000 feet, then continued upward at a gentler slope to approximately 17,000 feet. The entire observation lasted about 15 minutes, and the aircraft commander took photographs before the formation slipped out of view.

The three witnesses were First Lieutenant Glenn D. Mull (aircraft commander), First Lieutenant John Matt (navigator), and First Lieutenant Philip G. Kemp (weather observer). All three agreed on the basic details: the streaks appeared to form out of existing low clouds, no aircraft was visible, no unusual sounds were heard, and the plane's radar picked up nothing. Kemp suggested the formation might have been caused by a jet aircraft, though he noted that contrails at that altitude would be unusual. Matt thought that if the formation continued on its course, it would have crossed the California coast near Eureka, roughly 400 miles away, but he found it hard to estimate the actual distance without reference objects to compare against.

The Air Force Office of Special Investigations interviewed the witnesses and checked the weather records for that date and location. They confirmed that on August 2 at 1640 hours, an occluded weather front was moving through the area about 300 nautical miles to the west-northwest, with high pressure building to the southeast. The investigators also contacted the U.S. Navy's Pacific Fleet command and confirmed that no naval air operations were under way in the sighting area that day. Air Force records list the official conclusion as "cloud/contrail."

The full case file, as held by the National Archives, is reproduced below and consists of 8 pages.