“The pillar of fiery smoke and dust, still boiling up from where the bombs had gone off far underground, was being violently agitated at the bottom. A series of new flashes broke out, lifting and spreading the incandescent radioactive gasses, and then a great gush of flame rose. A column of pure hydrogen must have rushed up into the vacuum created by the explosion; the next blast of flame, in a lateral sheet, came at nearly ten thousand feet above the ground, and great rags of fire, changing from red to violet and back through the spectrum to red again, went soaring away to dissipate in the upper atmosphere. Then geysers of hot ash and molten rock spouted upward; some of the white-hot debris landed almost at the acid river, half-way to the armor-tender.
Out on the rolling skyline, fifty m
