"'The original flash lasted approximately 10 to 15 seconds. As the first flash died down, there arose in the approximate center of where the original flash had occurred an enormous ball of what appeared to be fire and closely resembled a rising sun that was three-fourths above a mountain. The ball of fire lasted approximately 15 seconds, then died down and the sky resumed an almost normal appearance.'
Although the energy yield of the Trinity explosion was one order of magnitude greater than the energy yield of the Port Chicago explosion, the characteristic temperature of the nuclear fireball and succeeding column of flame produced by the Trinity explosion was the same as the temperature of the fireball and succeeding column of flame produced by the Port Chicago explosion. The ball of fire and column of flame produced by the Port Chicago explosion were typical of a nuclear explosion, and were accurately used by Joseph O. Hirschfelder and William G. Penney to predict the characteristic behavior of the fireball and column of flame that did result from the Trinity nuclear weapon test.