tazination was found in regions which confirmed the forecast cloud tre- jectories, the requirement for H/24 through E448 hour tracking coverage was cancelled. 4s a result of the report from Rongerik, the advisory to CINCFACFL? at 2000 hours B Day included mention of fall-out at Rongerik plus ginor fall-out at Rongelap and other northern Marshall Islanis. The fall-out was attributed to an 2/12 hour change in the forecast air particle trajectory for the twenty thousand foot level. This trajectory, foraerly moving toward the EXE, was reforecast to move toward SE in a circular clockwise path through south to west. The CINCPACFLT advisory included no health hazard problem for surface and air routes, but that fall-out on Bikini-dtoll, as well as damage to structures, would delay reentry ser eral days. : During the trip back to Eniwetok on the night of B Day, the fleet en- countered a wide area of finely divided (arparently less than 5 micron) particles which caused top~side intensities as high as 350 or/hr. App- ropriate measures were instituted by the Navy Task Group Commander to the affect that all personnel not essential to open deck duties would remain indoors. Ship's weather doors were closed and the washiown systeas ope= rated intermittently to bold down the levels. Based on the advisory from the weather detachment that their instrne- ment was off-scale, the Air Task Group, on the morning of 8/1 day, sent a monitor by amphibian aircraft to check the Rongerik situation. This gonitor upon arriving over Rongerik, reported the atoll contaminated and requested permission to start evacuation of personnal. At about 1300 the monitor reported readings on Rongerik of 240 m/hbr at 250 feet and 3.2 r/br one inch off the ground. The Rongerik evacuation was comleted in two segments, the first group (8 people) coming out by B30 hours and the second group (20 people) by 5Y35 hours. The special AEC/NYOO Kwajalein Flight ABLE, requested the previous right, had been instructed to make an in-flight report upon reaching Taongt. (4 preliminary Flight ABLE report indicated 1350 m/hr on the ground at Rongelap, 445 m/br on the ground at Ailinginae ani zero for Wotho.) &ccordingly, it was decided to start a destroyer on the way to Ronrelap ia- rediately and to set up a Sh-16 amphibian with monitors to check the sur- face comtitions at Renzelap before dark. The destroyer was directed to be off Ronzelap ready to start evacuation at dawn the following day. 4 Trust Territory representative sith interpreter was requested to move by PSY from Kwajaledm to arrive et Ronzelap at the same tine, The Ss-15 was set up, two respemsible monitors were especially triefed to make reaiings at weist heicht, use several meters of the same type for comparison and to use different types for cross-check, An average reading of 1.4 r/ie made in the living ares of Ronzelap Island by these monitors was used in the decision the saze night to order the destroyer to commence evacuation operations at dawn, Evacuation operetions began about 0730, 3 March and