Steam cloud rises from underwater explosion of the atom bomb test BAKER develop into a towering cloud several thousand feet in the air. Waves crated by the explosion are moving away from the test site while tons of water are sprayed into the air, creating the white foamy portion surrounding the steam cloud. Bikini was chosen to be a nuclear testing ground for the U.S. government because of its location away from regular air and sea routes. Operation Crossroads BAKER was suspended beneath landing craft LSM-60 anchored in the midst of the target fleet. It was detonated on July 25, 1946, 90 feet underwater, halfway to the bottom in water 180 feet deep. No identifiable part of LSM-60 was ever found. Operation Crossroads was a series of nuclear weapon tests conducted by the United States at Bikini Atoll in mid-1946. It was the first test of a nuclear weapon after the Trinity nuclear test in July 1945, and the first detonation of any nuclear device following the Fat Man detonation on August 9, 1945. Its purpose was to investigate the effect of nuclear weapons on naval ships. Crossroads consisted of two detonations, each with a yield of 23 kilotons of TNT. Able was detonated at an altitude of 520 feet on July 1, 1946.