Upshot-Knothole Simon
1953 CE.
Shown on the map at 37.053°, -116.103°.
Upshot–Knothole Simon was a nuclear detonation conducted as part of the U.S. Operation Upshot–Knothole nuclear testing program. Simon was conducted on 25 April 1953 at the Nevada Test Site, and tested the TX-17/24 thermonuclear weapon design which had a yield of 43 kilotons. Test: Simon Time: 12:30 25 April 1953 (GMT) 04:30 25 April 1953 (local) Location: Nevada Test Site, Area 1 Test height and type: 300 feet (91 m) tower Yield: 43 kt The mass of radioactive material in the mushroom cloud did not disperse as expected, but stayed in a small volume of atmosphere as it traveled eastward. Finally, a couple of days later it became entrained in a severe thunderstorm over New York's Capital District, and most of the radioactive material washed out over a fairly small region (Washington and Rensselaer counties). Students in a radiochemistry laboratory at Rensselaer Polytechnic Institute in Troy, New York switched on their geiger counters only to discover radiation levels hundreds of thousands of times higher than normal. Assuming a radioactive spill inside the building, the students were rushed outside to safety – only to discover radiation levels even higher.
Text from the Wikipedia article Upshot-Knothole Simon, licensed CC BY-SA 4.0.