The Sighting
On the afternoon of June 24, 1947, Kenneth Arnold, a Boise businessman and experienced private pilot, was flying his CallAir A-2 near Mount Rainier, Washington, detouring to look for a Marine transport plane that had crashed on the mountain. Around 3 p.m. a flash caught his eye, and he watched nine bright objects fly in a loose echelon formation past Rainier toward Mount Adams, weaving between the peaks.
Arnold timed their passage between the two mountains, about fifty miles, at a minute and forty-two seconds, and worked out a speed of over 1,700 miles per hour, far beyond any aircraft of the day. He described the objects as thin, crescent- or boomerang-shaped, and their motion as "like a saucer if you skip it across the water."
How "Flying Saucer" Was Born
Arnold reported the sighting to reporters in Pendleton, Oregon, the next day. Bill Bequette of the East Oregonian wrote it up, the Associated Press carried it, and within days headlines were calling the objects "flying saucers" and "flying discs." Arnold had described how they moved, not how they were shaped; the press turned the simile into a shape, and every witness who came after knew what a UFO was supposed to look like.
The 1947 flying-disc wave followed immediately: hundreds of reports across the country over the next two weeks, including the debris found near Roswell, New Mexico, which the Army announced as a recovered "flying disc" on July 8.
The Explanations
Astronomer Donald Menzel proposed a mirage or ice crystals in the mountain air; the Air Force's Project Blue Book eventually filed the case as a mirage. Later skeptics have argued for a flock of American white pelicans, whose size Arnold could have misjudged as distance, or a meteor fireball breaking up. Each explanation covers part of the account; none covers the sustained formation flight and the speed Arnold computed, and he rejected all of them for the rest of his life.
What Arnold Did Next
Arnold became the first celebrity UFO witness. He investigated the Maury Island affair in Washington state that same summer, a case that turned out to be a hoax and cost two Army intelligence officers their lives in a plane crash, and he co-wrote The Coming of the Saucers with pulp publisher Ray Palmer in 1952. He kept flying, reported further sightings, and remained a careful, sober witness by most accounts until his death in 1984.
His case is where the subject begins: the first sighting to be widely reported, the source of the word, and the template for the wave that produced Roswell.
Frequently asked questions
What did Kenneth Arnold see in 1947?
Nine bright, thin objects flying in formation near Mount Rainier, Washington, on June 24, 1947, at a speed he calculated at over 1,700 mph. He described their motion as skipping like a saucer on water.
Who coined the term "flying saucer"?
Newspaper headlines, not Arnold. He said the objects moved like a skipped saucer; reporters turned that into "flying saucers," and the phrase defined the shape of UFOs for decades.
Was the Kenneth Arnold sighting ever explained?
Not to general agreement. Proposals include a mirage, ice crystals, a flock of pelicans, and a fireball. Arnold rejected them all, and the case remains the accepted starting point of the modern UFO era.