KOA E OPERATION 1, A The KOA device was a lend surface shot detonated at 0630M, 13 May 1958, at the west end of Gene Island, Entwetok Atoll. The approximate yield was 1.25 MT. Radar established the cloud height at 60,000 feet at 0637M, to the nortinest of Gene, The main segment of the cloud moved in a northerly direction and topped at 30,000 feet within thee first hour. 2. The P2V aircraft (Wildroot 2) reported over Enivetok at OS00M, and, using Yvonne as an axis, it was vectored along thirty-mile radials commencing with 240 degrees and increasing by 10-degree increments. tial runs recorded slight increases in background intensity. Ini- Maximm intensity was recorded over Janet at 1010M, vith 460 mr/hr at 1,500 feet. The entire legoon area was surveyed and the aircraft released at 1300M, 3. ReHour was declared at 1000M, and the initial helicopter survey was completed at 1030M. on Alice, Maximum ground reading was 40,000 mr/br recorded Other north=-atoll islands ranged from 130 mr/hr on Sally to 14,000 mr/hr on Irene. 4. Fallout forecast was genpeally accurate in extent and intensity. Tha main axis of the cloud was forecast to extend northeast of Gene on a hearing of 50 degrees. 5. area, vies gis It ts estimated that ali fallout dropped within the forecast Within twenty-four hours background in this erea commenced to rise, TAB A St