YELLCWWOOD EVENT OPERATION HARDTACK 1. The YELLOWNOOD device wes detonated at 1400M, 26 May 1958, ata position 5,000 feet southwest of Janet Island, Eniwetok Atoll. radar teports were unreliable. Initial Pilot reports from sampler aircraft esti- mated the clo:d height at 50,000 feat, cloud base at 30,000 feet, with initial direction true bearing 250 degrees at 20 to 25 knots. 2. The P2V"g cleared into the area at 1430M, One PoV was vectored over the northeast islands to determine whether or not the sampling roskets had teen fired. The second P2V was vectored between Yvonne and Leroy, As the cloud moved west-southwest of the lagoon, ons P2V was used to sumray the northern section of the lagcon. was declared at 1530M, The area was garerally clear, and resntry The activities of the office were greatly hampered by slow comminications with the tracking aircraft through Manhunt. 3. The survey helicepter tcok off at i604M, was made at Alice: 200 r. The highest reading Other readings along the northern chain areraged from 4 mr/hr to 10 nr/hr. 4. The fallcut had been predicted to fall along a bearing of 260 degrees for 200 miles; however, the astual fallout pattern extended to only150 milas. BEST COPY iY AiLABLE TAB A an oq