l, Gaus" te ete” mie ' ">. ¥$,006 = mee ines a : 7 ‘Se KOON cloud reached an altitude om the order of 50,000 to feet. htr Rad Safe operations for KOON were successfully cofdyeted and reeulted in mech tinely informatios on Post-evens comdiitone.- This effort indicated that the lowest section of ths cloud stem, up ta perhape five thousand feet, moved to the west at —pene velocity of about fifteen mots. Contact was madu with t segnent of the cloud by scloud tracking aircraft which reported & maximm intensity of 1§ Mr/Hr at plus five hours fifty miles to the west of Ground Zero (BIKINI). Continued fallout and dispersion dise sipated this material rv to ite arrival at Eniwetokse The middle seguents of the cloud (six to twenty-five thousand feet} initially moved north and then east~northeast at about fiftees imate. Con» tact was also made with fallout from this portion of the cloud at the forecast poeition. It wae this level of the cloud which subs sequently caused fallout on Rongelap and Rongeril Atolls. The tog section of the cloud, up to fifty thousand feet, moved to the caste northeast at approximately thirty mots. Excluding the Rongelap/ Rongerik contamination, there was no evidence of significant falle out inside or outaide the PPG. 2. GENERALS ‘ Be os of ormations Gloud tracking information for KOON was available fros five sources, The contribution of cach of these sources, which are listed balow, will be discussed in sudsecquont paragraphs, ‘ Sampling Aircraft Reports Sweot~Sour Reporte Special Cloud Tracking Flights Weathor Reconnaissance Flights ‘ APOAToL Plights be Overall, Cloud Movement (within the =PG): The Bikind winds observed shortlyaftur shot timo were as shown by the hodographs, From the hodegraphe it can be scon that the KOON cloud, whose maximm height was of tho order of fifty thoue sand fcet, was influonced by two wind shoars. Tho lowest lovol of tha cloud (surface to four thousand fect) was influonced by the winds from the cast which averaged sixtcen cuts. Since this sognent of the cloud was so thin vertically all but tho lightost particles should have fallon out within a comparatively short distance of Ground Zero. This undoubtedly wis the caso since it was contacted only to the west of GZ and because the ground station at Eniwotole rcpartod no radiation readings attributable to KOON, Tho initial movenont of the mid= dle cloud (four to twonty~five thousand fcot) was influenced by the INCLOSURE 6 ° Me25