a SECRET 7AB_B RADSAFE NARRATIVE SEQUENCE OF EVENTS cast cloud movement on true bearing of 300° out to 800 miles from @. The Bel day search by P2V out to 375 miles on ea forecast significent eloud movemext on a true bearing of 330° disclosed no transient shipping except the General Patrick, whose course and speed would take hae outside the hazardous area by snot time. At the midnight briefing, the forecast offered a less favorable comiition in the lower levels (10-25 thousand feet). Resultant winds at about 20,000 feet were forecast in the direction of Rongelap and Rongerik (Figure 1); however, it was considered that the speeds ani altitudes did not warrant a conclusion that significant quantities and levels of debris would be carried out so far. TARE Site was forecast to be well in the fall-out area and NaN Site to be in a fairly high intensity area. Since the 5-1 day forecasts gave winds tenting significantly toward SE, a decision was mede at the mide night triefing to search on B day ahsed of the cloud, i.e., cantered on true bearing af 65° out to 600 NM and to warn ships out of the 450 HM ninjas radius. . The routine H-18 hour advisory to CINCPACFLT indicated a0 significant fall-out forecast for populated Marshall Islands, and no safety pro- blems on air or surface routes except surface routes between 275° clock= wise to 80° out to a radius of 450 NM with possible significant fall-out in this area. Wo known shipping was in the forecast fall-out area. The surface radex was forecast for shot time to shot plus six hours to be oriented in a narrow sector to the northeast and a wide sector to the south, with an additional circular radex area around G2 of radius 15 wiles (Pigures 1 and 2). The sector pointing at Rongelap was considered insig- nificent due to the low altitudes from which fall-out could occur and due to the very light winds acting on the levels involved. At the 0430, 1 March briefing, no significant change had been observed in the midnight winds received, however, a radsafe reconmendation was maje to move the task force skips radially further out from the minis rum of 30 BM to a cinimun of 50 NU in the SE quadrant. The low level cloud was ferecast to overrun the TARE camp ani move on to the east with a trong posaibility of overrunning NAN, The resultant winds pointing at Rongerik and Rengelap were light ani were not forecast to transport sig~ nificant debris to these atolls. bt 0625 the BRAVO detonation was accomplished without hazard to task force personnel. The bunker firing party reported in sefe, but by O715 the radiation levels ware reported rising at the bunker. levels contimed to rise to about 25 r/br. SECRET — see ee These The firing party was con- RESTRICTED DATA iv ESE*ST ACT = 188 NT Tt By the morning of B-l day, the wind patterns (forecast and actual) ware favorable but the trem! of the observed resultant wind patterns was toward an unfavorable or mrginal condition, No transient shipping was reported on the B-2 day P2V sweep centered on a significent fare-