Like crime scenes on a detective's map, the scattering of reports began to show a pattern. The "ear-witnesses" who flagged the loudest booms were centred around Sellwood Bridge, one of the dozens of bridges that cross Portland's Willamette river. Sure enough, when police went to inspect Powers Marine Park just south of the bridge, they found a large, recently fired, pipe bomb. The investigators think the sound of the bomb travelled around the city because of low cloud cover and the focusing effect of the nearby river bank. Read more
Emergency dispatchers in the Portland area received several reports of a loud boom Sunday evening. The FOX 12 newsroom also received numerous calls from people reporting what sounded like an explosion. The reports came from as far east as Boring and as far north as Vancouver. The source of the boom is unknown. Read more
A loud mystery boom baffled many people in Portland Sunday and authorities were still trying to figure out what it was on Monday. There were numerous reports of a loud explosion at 8:05 p.m. Most of the reports were clustered in Southeast Portland. Read more