FLATHEAD EVENT OPERATION REDWING , 1, The FLATHEAD Shot was fired at O&26H, 12 June 1956 on a barge i— Jocated approximately one~half mile South of YUROCHI Island (DOG) in the BIKINI Atoll. The cloud reach et. The lower portion of the cloud and stem moved to the West at approximately 15 knots. 2. The fallout forecast for FLATHEAD was calculated on the basis of a water surface burst and a Program ‘THO fallout mummary on H+1 Day indicated the fallout sector as 210° through O50" extending 100 miles with probable hot line onbearing 010° with an average intensity on the surfece of the water of 1 mr/hr. The plus 8-hour summary gave seme sector with hot line definitely fixed on bearing of 310°. Program TWO surveys confirned the fallout forecast to be within the acceptable error of forecesting. | 3. Cloud penetration aircraft reported the middle and upper portion of the cloud moving to the northeast at Ht] Hour. The cloud contimed te move in a general north-northeasterly direction throughout H+3 Hours. . The aerial monitoring (F2V aircraft) reported the ENYU (NAN) air~ strip te be free of debris and radiological hazards, Based on survey information Reentry Hour was established at 0830M, 12 June. The initial helicopter survey at H+3 hours reported fallout still occurring over the reef and lagoon in the vicinity cf ‘YUROCHI (DOG). Fig dif Sanz, anole,taf. “ Sire HUT -"s — * tithe NOLS sere In general, the initial