£, «$s in previous operations » weather was 2 major problen, particularly with regard to winds aloft for fall-out considcrations, were experienced because of unacceptable fall-out patterns. Oclays The tests were carried out during a period of the year when the weather in the Uarshell Islands area was reasonably favorable; it was not an unusual season from a climatological point of view, Suture tests mist expect sindlar delays due to weather unless flexible tiring techniques such as firing on barges in the open ocean or sir drops are developed which will mininize the amount end the activity of fall-out, 8. Raddological Safety (1) Since six shots in the megaton range were scheduled for the operation, the isdsafe Plan placed particular emphasis on the possibility of fall-out on populated islands and trensicnt shipping. Forecasting ridic= active fall-out for C.STLE wos initially seriously handicapped by the absence of definitive data on the effects of very high yield (megaton) devices. Information from Operation IVY (IIKE Shot) was extremely limited and as 3 consequence misleading in many respects, In particular, early C..STLE , experience indicated thet fall-out periods on the order of six to twelve hours. while adequate for ylelds obtained prior to IVY, were insdequate for C..STLZ. It wes spparent that pre-shet forecests would be required of wind conditions for periods up to H plus 16 to H plus 24 hours with = high degree of accuracy in order to ingurc that the significant fall-out would trke place in sccepte able areas during this period of tise, Generelly, this requirement involved the forecasting of the stability of wind patterns, or the expected limits on the variation of the pattern during the period of fall-out. Further, it required wind forecasting for several different tines end many seographical positlene tnrowwbout the projected fall-out ares.tacmcr.tousunnort 3 caw.