Hiroshima remembers the dark day

"Flash" burns, caused directly by the almost instantaneous radiation of heat and light at the moment of the explosion. Burns resulting from the fires caused by the explosion. Mechanical injuries caused by collapse of buildings, flying debris, and forceable hurling - about of persons struck by the blast pressure waves. Radiation injuries caused by the instantaneous penetrating radiation (in many respects similar to excessive X-ray exposure) from the nuclear explosion; all of these effective radiations occurred during the first minute after initiation of the explosion, and nearly all occurred during the first second of the explosion.