At 8:15.17, the bomb slipped from the plane. Tibbets (the bomber pilot) turned the plane as hard as he could and put it into a dive to gain speed. It would take forty-three seconds for the bomb to reach its detonation altitude, a little less than two thousand feet. No one knew for sure if, in that brief time, the bomber could get far enough away to survive what was coming.
One of the crewmen counted seconds in his head. When he hit forty-three, nothing happened. He didn't know that he had been counting too quickly. For an instant, he thought the mission had failed.
Exactly as the thought crossed his mind, the sky over the city ripped open in a firestorm of color and sound and felling wind A white light ten times the intensity of the sun, enveloped the plane as the flash and souund and jolt of it skidded out in all directions. The tail gunner, looking out the back of the plane through his goggles, thought that the light had blinded him. Tibbets's teeth began tingling, and his mouth filled with a taste of lead. He would later be told that it was the metal in his fillings resonating with the radioactivity of the bomb. He looked ahead and saw the entrie sky swirling in pink and blue. Next to him, the copilot scribbled two words in his diary: MY GOD!
Behind him, the tail gunner's vision cleared and he saw an eerie shimmering warp in the air over the city, ripping towards them at one thousand feed per second. "Here it comes!" he said. The shock wave slammed into the plan, pitching the men into the air and back down again. In confusion, someone yelled "Flak!" Then a second wave, a consequence of the force of the explosion hitting the ground and then ricocheting upward, smacked them and the plane heaved again. (Page 300)
In reading Hillenbrand's Unbroken I learned that most POWS considered this bombing a life saving event for them because talks of a mass killing of prisoners had intensified and were possibly scheduled two weeks after this attack.