. . +. q : ah aged fifteess inctes This noveusn was confitaed bya cloubtracicing zim. . craft flying sixty miles weet sorthwes® of Growsd Zere zh cigh® tioumnd feet; the maximus intensity reported was 60 Kr/Hze Based om the positica of thig contact and the forccas® sir trzjectoricg, if is believed that this som * taminatdor subsequently passed to the north of ENIWETO® .TOLL. The middle 4. lavel of the cloud. (twenty to sixty thousand feat) moved to ths eastencrta= east at a spced of approximately fiftcess knots ~ the wind velocities having decreased aftcr shot times Only one contact (at plus five hours) was nade with f level. of : from this level of the cloud (see ,ppendix I). The highest. mshroem probably moved ta the north: and west bub none of the tracise. ing aircraft made contact with fellout from thia portion of the cloude 3- S.MPLING RCE. Ss As in the case of previous shots, these reporta were recorded by Rad. Safe persormel. aboard the Command Ship fram nlus twe ta plus five bourse. Reports from these aircraft provided the first data avatlable on initial. cloud movement and confirmed the accuracy of the forecase aim radexm (see. Appendix IT); he S-EETWGOUR RSs These reports were submitted by any aircraft encountering radioactive contamination and not reporting by other means. No suck: reports were re— coived following UNION. Se 5S 5 TR..C ui S:. _ & The initial phases of the UNION cloud tracking effort duplicated those which were so successfully employed for previcua# CASTLE shotsy Two . “B=a29'¢, \ILSON TO and VILSON THRES, were placed tm 4 holding pattern fifty - miles west of Ground Zero at plus-two hours» 1s will be seem fram .ppendix T, the location and orientation of this pattern is suck that any cloud seg= ments moving toward either ENTVETOR or UJELAND should be intercepted by at least one of these aircraft. ‘/ILSON THRES initially flew in this pattern at six thousand feet but was subsequently ordered to sight thousand feet in order to maintain flight under visual conditions. sand fcet throughous his mission. WILSON T..0 operated at ten thoum b. /% approximately 2130 Zebra Nilson was requested to descend to one thousand feet and make a survey of the southern islands of BIKINI .TOLL ank the aipetgip in particular. This effort ved that there were no portions of GILDA (the atomic cloud or ite fallout) endangering either the fleet or tha southern islands. The zirstrip waa found to have been flooded and lit— tered with debris but the radixtion reading at one thousand feet was only & Mr/Hr, Qn the basis of this information it was determined that it was safe for the fleet to approach the atoll amd to begin the helicopter phases of the detailed Rad Safe survey, WILSON THREE returned to the racetrack and resumed orbiting ot eight thousand fect; the increase in altitude was authorized in. order that the flight could be conducted under visual conditions. at 2327 Zebra “WILSON THREE made the first contact with the westward moving portions N=33