Firestorm-made thermal column. Fire (1) makes hot air (2) to rise forming storm-winds (3) towards the fires. A = Pyrocumulonimbus. Source
Wildfires are dangerous, but firestorms are downright terrifying.
They happen when conditions are right for the soaring air column over fire to develop its own momentum (PDF). This makes ground winds turbulentand they pour into the center of the conflagration, increasing its heat and spreading it around.
The process becomes self-sustaining. In fact, it will continue to grow as long as there is fuel available.
Firestorms occur naturally. As well – and this is heartbreaking – human beings sometimes start them, accidentally or on purpose.
Be aware that we’re going to look at representative World War II firestorms here – Stalingrad, Hamburg, and Hiroshima – as well as the deadly but, somehow, more humane natural or accidental ones. (I have set the Hamburg video, filmed by a local fireman, to stop before it gets to the bodies.)
Here, then, in chronological order, are ten of the worst natural and man-made firestorms over the last one hundred years.