Among the numerous observers of these two detonations was an Army doctor trained as a radiological safety monitor. He made the following observations of ABLE and BAKER from a Navy aircraft approximately 20 nautical miles from each detonation: ABLE: At twenty miles [it] gave us no sound or flash or shock wave. .. Then, suddenly we saw it -- a huge column of clouds, dense, white, . boiling up through the strato-cumulus, looking much like any other thunderhead but climbing as no storm cloud ever could. The evil mushrooming head soon began to blossom out. It climbed rapidly to 30,000 or 40,000 feet, growing a tawny-pink from oxides of nitrogen, and seemed to be reaching out in an expanding umbrella overhead. For minutes the cloud stood solid and impressive, like some gigantic monument, over Bikini. Then finally the shearing of the winds at different altitudes began to tear it up into a weird zigzag pattern (4: 55). BAKER: This shot in broad day, at fifteen miles, seemed to spring from all parts of the target fleet at once. A gigantic flash -- then it was gone. And where it had been now stood a white chimney of water reaching up and up. Then a huge hemispheric mushroom of vapor appeared like a parachute suddenly opening. ... By this time the great geyser had climbed to several thousand feet. It stood there as if solidifying for many seconds, its head enshrouded in a tumult of steam. Then slowly the pillar began to fall and break up. At its base a tidal wave of spray and steam arose, to smother the fleet and move on toward the islands. All this took only a few seconds, but the phenomenon was so astounding as to seem to last much longer (4: 93). Figure 7 shows the BAKER detonation (A). Credits for figure 7 and the subsequent photographs follow the references at the end of this chapter. 4.2.1 Background and Objectives of CROSSROADS. After the atomic bomb attacks on Japan had abruptly ended World War II, many military leaders felt that military science was at a crossroads. The admiral who directed CROSSROADS declared that "warfare, perhaps civilization itself, had been brought to a turning point by this revolutionary weapon." With this thought in mind, he named the initial postwar test series (3: 17). As early as August 1945, the Chairman of the Senate’s Special Committee on Atomic Energy proposed that the effectiveness of atomic bombs be demonStrated on captured Japanese ships. In September, the Commanding General of the Army Air Forces put the question of such a test before the Joint Chiefs of Staff (JCS). The ensuing discussion and recommendations led President Harry 74