For decades this image was misidentified as the mushroom cloud of the bomb that formed at c.8:16. However due the clouds much greater height and time of day, it was identified in March 2016 as the cloud created by the firestorm that engulfed the city, a fire that reached its peak intensity some 3hrs after the bomb. The image with the incorrect description featured prominently in the Hiroshima Peace Museum up to 2016, though not cited, it had initially been misattributed and presented to the public by the US, with the popular world touring 1955 <i>The Family of Man</i> exhibition. Earlier estimates derived solely from the quantity of fuel in the city, and more recently on the height of the Pyrocumulonimbus cloud both point at approximately 1000 times the equivalent energy of the bomb having been released by this firestorm. During the birthing of this cloud, 20 mins after detonation soot filled black rain began to fall on survivors. Climate scientists suggest that 100 of these identical firestorm clouds could cause 1-2 celsius of "catastrophic" global cooling, which is termed a small "nuclear winter".
United States Army
1945-08-06
<a rel="nofollow" class="external text" href="https://www.nytimes.com/2016/05/24/science/hiroshima-atomic-bomb-mushroom-cloud.html">New York Time</a>