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[…] The impression created by viewing a burnt-out city pales beside the fire itself: the howling of the firestorm, the cries and moans of the dying and the crashes of the falling bombs. […]

The reason for the damage being so serious and, above all, for the unusual number of deaths compared with previous raids, is the fact that firestorms developed. They, and in particular the one during the second major attack on the night of 27/8 July, created a situation which must be described as novel and hitherto inconceivable in every respect.

[…]

Firestorms and their characteristics are established phenomena well known in the history of urban fires. The physical explanation for them is simple. As a result of a combination of a number of fires the air overhead becomes heated to such an extent that, because of its reduced specific gravity, it develops a tremendous upward pressure which creates a very strong suction effect on the surrounding air masses pulling them towards the center of the fire in a radial direction. As a result of the firestorm and, in particular, the tremendous suction effect, winds are produced which are even stronger than the well-known wind strengths [1-12]. As in the case of meteorology so also in the case of firestorms the air movement is produced by a rebalancing of differences of temperature. But, while in the case of meteorology these temperatures are generally of the order of 20–30 degrees Celsius, in the case of firestorms there are temperature differences of 600 or even 1,000 degrees. This explains the huge force generated by the firestorms which cannot be compared with normal meteorological processes. […]

The development of a firestorm is encouraged or hampered by the architectural conditions of an affected area in the same way as by the type, extent and size of the original fires. In Hamburg the firestorms originated in areas in which the buildings were close together and densely populated and in which, therefore, the type and density of the buildings affected already provided favorable preconditions for the development of a firestorm. The affected areas in Hamburg were characterized by narrow streets with big blocks of flats with large numbers of courtyards, terraces etc. In these yards fireballs could develop very rapidly which became, in the truest sense of the word, mantraps. The narrow streets formed fire channels through which the long flames were whipped.

As a result of the concentric enemy attacks and the heavy concentration of incendiaries a huge number of fires developed in such areas in a very short time. It should be noted in particular that there were not only roof fires but, as a result of phosphor bombs and liquid [petrol and rubber] bombs, in many areas large blocks of flats were suddenly set alight from the bottom floor. The fires could develop with incredible speed since roofs had been torn off, walls had caved in, windows and doors had been torn out of their frames or smashed by concentrated attacks with high-explosive bombs and mines and on these the fires could feed without any hindrance. For these reasons, the intermediate stage of the fire's development, which in the case of previous raids it was possible to combat and which produced some of the biggest successes of the Hamburg civil defense forces, did not occur. For in many places extensive fires developed in a very short time. And because of the laws of physics, which have been outlined above, a firestorm developed in every one of these districts where there was an extensive fire. The suction effect of the firestorm in the larger or largest of these extensive fire areas had the effect of pulling in the already superheated air of the smaller fire areas. So the cores of the most ferocious fire areas sucked the fires from the smaller fire areas towards them. As a result of this phenomenon, fires in the smaller fire areas were pumped up as if by bellows, since the central suction effect of the largest and strongest extensive fires had the effect of pulling in the surrounding masses of fresh air. In consequence, all the fires grew into a single huge conflagration.

In order to form an impression of this massive firestorm which was created from countless smaller fires, one must bear in mind that, for example, the area affected by the major raids on 28 July was some 5.5km long and 4km wide, i.e. 22 sq. km in extent.

[…]

The speed with which the fires and firestorm developed negated all plans and every attempt by the population to fight them. Houses which in the previous raids had been able to be saved by the brave actions of the civil defense and other forces, fell victim to the flames. In many cases escape routes were cut off before the need to escape became apparent.

After the alarm was sounded, the civil defense forces waited in their shelter, the firefighters in the extended civil defense and factory defense units were at their posts awaiting the start and progress of the raid. Sticks of high-explosive bombs shattered the houses down to their foundations. Already a short time after the first explosive bombs had fallen, a huge number of fires had started as a result of a massive amount of incendiaries mixed with high-explosive bombs. People who now wanted to leave their shelters in order to see what was happening or to fight the fire were met by a sea of flames. Everything around them was on fire. There was no water and, in view of the huge number of fires and their extent, any attempt to put out the fire was useless from the start.

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The fact that even now on some days up to a hundred or more corpses are being found and removed provides only a feeble impression of what happened. Overall, the destruction is so devastating that, in the case of many people, there is literally nothing left of them. On the basis of a layer of ashes in a large air raid shelter, doctors could only provide a rough estimate of the number of people who died there, a figure of 250–300. It will only be possible to produce an exact figure when all the people who were living in Hamburg at that time who are still alive have once more registered with the authorities.

The horrific scenes which occurred in the area of the firestorm are indescribable. Children were torn from the hands of their parents by the tornado and whirled into the flames. People who thought they had saved themselves collapsed in a few minutes in the overwhelmingly destructive force of the heat. People who were fleeing had to make their way through the dead and the dying. The sick and frail had to be left behind by the rescuers since they themselves were in danger of burning.

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And each one of these nights of fire and flames was followed by a day which revealed the horror in the pale and unreal light of a smoke-covered sky. The heat of high summer, increased to an intolerable degree by the embers of the firestorm, the finest of dust particles from the churned-up earth and the ruins and rubble of the destroyed city which penetrated everywhere, soot and ashes raining down, and again heat and dust, and over everything a pestilential smell of decomposing bodies and smoldering fires bore down on the population.

And these days were followed by new nights with new horrors, even more smoke and soot, heat and dust, with still more death and destruction. People were given no time to rest or to plan the rescue of their belongings or to look for their relatives. The enemy drove on with ceaseless attacks until the work of destruction had been completed. His hatred reveled in the firestorms which mercilessly destroyed people and things with equal force.

The seemingly utopian [sic!] vision of a major city in rapid disintegration without gas, water, light and transport, with formerly flourishing residential districts turned into deserts of stone, had become reality.

The streets were covered with hundreds of corpses. Mothers with their children, men, old people, burnt, charred, unscathed and clothed, naked and pale like wax dummies in a shop window, they lay in every position, quiet and peaceful, or tense with their death throes written in the expressions on their faces. The situation in the air raid shelters was the same and made an even more gruesome impression because, in some cases, it showed the last desperate struggle which had taken place against a merciless fate. Whereas in one place the occupants were sitting quietly on their chairs, peaceful and unscathed as if they were sleeping and had unsuspectingly been killed by carbon monoxide gas, elsewhere the existence of the fragments of bones and skulls showed how the occupants had sought to flee and find refuge from their prison tomb.

It will be impossible for anybody ever to imagine or conceive the horrific and gruesome scenes which must have occurred in numerous air raid shelters which were buried. Posterity will only be able to maintain a respectful silence in the face of the fate of these innocents who fell victim to the bloodthirstiness of a sadistic enemy.

The behavior of the population which at no time and nowhere displayed signs of panic and was worthy of the greatness of this sacrifice showed its commitment. It befitted the Hanseatic spirit and character which, during the raids, found its finest expression in comradeship and assistance and solidarity and, after the raid, demonstrated through its deeds an unshakeable determination to rebuild the city.