Atmospheric Physics Part III
From this historical distance, I cannot give a definitive answer to what causes a fire storm to start, but there are strong hints that Mr. Dyson’s observation was on the mark. Tokyo is the easiest to explain. There was a 50 knot gale blowing when the bombing took place! Mother Nature provided a forced draft system to feed oxygen into the fires. This was more of a massive forest fire than a fire tornado, but the results were similar.
The Hamburg raid took place in late July 1943. The bomb load consisted of 4000 pound block busters and incendiaries. The block busters to create a pile of flammable rubble and the incendiaries to light the pile. An important point is the use of thermite incendiaries. These do not require air to support combustion and burn at much higher flame temperatures than an ordinary flame. If the bomb runs are well aimed and concentrated in time, you can create a very hot column of gas to jump start a vertical circulation in a pre-existing, vertically unstable atmosphere. Once the circulation starts, it brings in oxygen to support combustion. The thermite combustion allows the fire to be sustained even during periods of oxygen depletion. This ability to sustain itself is not present in the aftermath of a nuclear explosion. (see links in previous post regarding explosives for discussion of the necessary structure to support detonation). The raid on Dresden was structurally similar. So there actually is good reason to believe a fire storm is unlikely to be created by a nuclear weapon. Without the fire storms, there would be much less smoke and therefore much less chance of a huge dark cloud blocking out the sun. Further confirmation of this skepticism was provided by the Kuwaiti oil fires. Once again, we find more hype than science in the TTAPS scenario. And since “global warming” is supposed to be caused by a combustion process, it means we should examine this a bit more in a future post.