The eastward moving debris reached the Americas on March 7 and 8, indicating an average west wind of about 40 knots, in good agreement with the few wind observations avellable in the upper troposphere. Although the progression of debris to the west appears to be in good agreement with the 5,000-feot trajectory, indicsting that the transport occurred in the trade wind layers, it is entirely possible that stratospheric debris moving with the wper level easterlies contributed to this fallout also. The most striking fact which emerges from a study of the fallout in the period following the Bravo test is the tendency for the debris to remain in the tropical latitaies. By far the largest amounts of fallout occurred in the latitude bend from 10°S to 20°N, with occasional excursions into the more temperate latitudes of esch hemisphere, particularly in the Americas. An example of this can be seen in the southwestern United States in the period beginning March 15. At this time, a deep low pressure system extending through most of the troposphere was located just off ths west coast, with strong southwesterly winds over the southwestern states. This depression moved slowly eastward so that by Mifeh 18th, the southwesterly winds were over the Mississippi Valley... dnexaminstion of the fallout maps reveals that fallout during this period was associated with the soutinresterly winds, which carried debris from the tropical regions. It is significant that. this fallout was independent of precipitation. The highest fallout values occurred during the first three days of the period | when there was no precipitation, and even on the 18th, when there were several stetions reporting precipitation, the fallout occurred in the region dominated by the southwesterly winds and was not closely sssociated with the existence of precipitation. A somewhat similar series of events occurred in the period March 21-25, although precipitation was more widespread in this case and may have had more influence on the observed fallout patterns. ROMEO The second burst of the Castle series, Romeo, also a high-yield burst of the same order of magnitude as the Bravo test, was detonated from a barge at 1830 GCT, March 26, 1954. mq 2.2 The resulting cloud of debris reached to 110,000 feet, with the base of the musin'oom top at 62,000 feet. The wind observations associated with this burst speed above 80,000 feet to a maximum of 92 knots from the SE at the top of the highest observation, 95,000 feet. Although the trajectories (Figure. 2.3) at all levels in the troposphere moved westward initially, the 30,000- and 0,000-foot trajectories curved northward -Jea ey showed light easterly winds at virtually all levels increasing in