MAGNOLIAEVENT OPERATION HARDTACK io The MAGNOLIA device was detonated at O600M, 27 May 1958, 3,000 faat southusst of the center of Yvonne Island. The cloud rose immediately to 44,000 feet and stabilized at 41,000 feet with the base at 15,000 fect. Radar confirmed this ncsition, and the initial cloud movement was westerly. The middle segment remained over ground zero, and the upper and lover levala moved on a bea-ing of 250 degrees. 2. The P2V aircraft was vectored from Alvin to Keith at 0633M, and it reported reaqings of Zero at 500 feet. The northern chain was then surveyed, with the highest reading recoried ovar Alice: 5 mr/hr, at OS47M, Tne lagoon srea was svapt in 10edegres increments, and in the center of the lageon at 500 fost, 7 r was recorded at 0735M, Tha aircraft was considered contaminated and was instructed to wash down at Fred. Reentry was declared at 0730M, 3. A helicopter ground survey was initiated at 0745M. The highsat reqding wes racorded at Alice, with 22,000 mr/hr, which 1s attributed to the YELLOWWCOD event. Other islands in tha northern chain rangsd ffom 2 ne/hr to 120 mr/hr, with Yvonne reading 1,200 to 2,000 mr/hr. 4.0 A second helicopter survey wae nade at 1430M. The southern chain = indicated only background with tha exception of Leroy, which r2ed 35,000 mr/rh at twenty-five feet, This high reading is attributed to a amall section of the cloud which did not move out of the legcon as anticipated. reading accounted for the contamination of the P2V, BEST COPS TAB A This high ‘04 iLABLE J 21