Originating in Bellingham in March, police initially believed the work to be vandals using BB guns. However the pitting was soon observed in the nearby towns of Sedro Woolley and Mount Vernon and by mid April, appeared to have spread to the town of Anacortes on Fidalgo Island.
Within a week, the news and the so-called "pitting epidemic" had reached metropolitan Seattle. As the newspapers began to feature the story, more and more reports of pitting were called in. Motorists began stopping police cars to report damage and car lots and parking garages reported particularly severe attacks.
Several theories for the widespread damage were postulated:
By April 15, close to 3,000 windshields had been reported as affected.
Finally, Sergeant Max Allison of the Seattle police crime laboratory stated that the pitting reports consisted of “5 per cent hoodlum-ism, and 95 per cent public hysteria.” By April 17, the pitting suddenly stopped.
The Seattle Windshield Pitting Epidemic as it is called has become a textbook case of collective delusion (not "mass hysteria" as reported). Although natural windshield pitting had been going on for some time, it was only when the media called public attention to it that people actually looked at their windshields and saw damage they had never noticed before.