outthe Task Force for the information and compliance of all. Area fallout plots considered the entire area of significant fallout, to include infinity isodose lines of at least fifty roentgens, and in some cases down to ten roentgens. These plots, being more general in application, were considered, with the RADEXES, at command briefings for the overall fallout impact on populated atolls in the vicinity of the shot atoll. In support of the above, the previousiy mentioned hodographs (see A) played an important role in the determination of the radsafe picture at any one time. These wind vectcr diagrams graphical-~ ly illustrated the favorable or unfavorable wind patterns at the two atolls in the PPG. As a general rule, the high and low winds in the Marshall Islands are relatively stable, being east northeasterly to easterly in the lower tradewind levels (surface to about 20,000 feet) and easterly in the high levels above the tropopause (above 6,000 feet). In view of these wind directions at various levels (see also Appendix A, Meteorology) a discussion of favorable and unfavorable hodographs is primarily concerned with those mid-levels where the winds are most variable and invcive the most significant portion of the cloud from a fallout standpoint, i.e., between 20,000 and 60,000 feet. The limiting criteria for wind patterns were dever- mined by the populated atolls of Ujelang, Eniwetok, and the Marsnail Islands to the east of Eniwetok. In general, wind conditions ac- ceptable for a shot at Bikini are acceptable at Eniwetok., verse is not always true. The con- An additional consideration is the fact 185