![The Hiroshima atom bomb cloud 2–5 minutes after detonation[136]](https://cdn.deepswipe.app/images/0.2.0/1fe19cd9b0716c929c112cc02ae8c38dde20d30cbf03e2bc2f6a898c426c72c9.jpg)
Hiroshima's warning had already ended
On the morning of 6 August 1945, Hiroshima's air raid warning was cleared. Many people were outside, going about ordinary life, when everything changed.Hiroshima Atomic Bombing: What Survivors Saw

One flash, then one boom
Survivors described a pika(Japanese for a sudden flash.)—a brilliant flash—followed by a don(Japanese for a deep boom or blast.)—a crashing sound. Many thought a conventional bomb had exploded right beside them.Hiroshima Atomic Bombing: What Survivors Saw