James Ziegler and W Lanford first detected sea-level single-upset events in 1979 and in the decades following much of the research was done in Leadville, Colora

James Ziegler and W Lanford first detected sea-level single-upset events in 1979 and in the decades following much of the research was done in Leadville, Colorado which has an altitude of 3096 meters. Unfortunately I can't find a link for the 1979 headscratcher at the moment. I will edit this comment if I do.