Closer in towards Winson Green the effects of the heat from the fireball were more pronounced. The foliage in the countryside had crisped as if autumn had arrived. Smaller brushwood was smouldering. Haystacks were burning and paintwork on buildings and vehicles in the path of the heat-wave blistered. At Aldridge, and at other places within about twelve kilometres of the fireball, people caught in the open received burns which needed immediate hospital treatment. At this range curtains and other materials inside rooms that were exposed to the heat pulse began to smoulder and in some cases burst into flames. Any lightweight objects such as newspapers, canvas and empty packaging in the open soon caught fire.
Closer to the fireball heat levels became even more intense, so that almost any lightweight material subject to the heat-wave burst into flame while metals and other objects were scorched and distorted. At these ranges the clothing worn by individuals no longer gave effective protection against the heat. Clothes burned off, and people in the open received such extensive burns that their prospects of recovery, even with first-class medical assistance, were negligible. Fires were started inside and outside buildings to an increasing extent as the epicentre was approached, with apparently almost total conflagration occurring within three to four kilometres of Winson Green.
The enormous blast pressures released by the nuclear device followed the heat-wave within a matter of seconds. Those in the open who had suffered severe burns had no more than a few seconds in which to register shock before the blast-wave hit them. Those inside buildings who had already experienced the overpowering flash of light were now subject to the effects of blast. Within a second or so of the detonation the blast-wave hit the city centre beneath the fireball. The enormous pressures had the effect of instantly crushing all buildings below it so that what remained was only a levelled mountain of rubble. The blast-wave then roared and crushed its way outwards from the centre utterly destroying everything in its path. No structures above ground level were able to withstand the tremendous pressures and the coincident wind speeds resulting from the blast. Within three kilometres of Winson Green nothing survived, every building and structure being reduced to rubble and strewn across the roads so that the entire area looked like a gigantic rubbish heap. The effects of the blast-wave began to decline as it travelled outwards, so that between three and six kilometres from the centre a few of the smaller and more strongly constructed buildings remained standing, some at crazy angles and missing many portions of softer construction around reinforced concrete or steel skeletons. Even these few remaining buildings were in such a twisted and derelict condition that they were hardly recognizable as the original structures. They were surrounded by the gutted remains of lighter buildings of modern construction such as hospitals and schools, demolished beyond recognition. All domestic structures within this area suffered similarly, with most brick houses collapsing under the effects of the blast-wave.
Those who had suffered the most agonizing effects of the heat-wave were mercifully killed by the blast-wave that followed. People who had been indoors were now buried beneath mountains of rubble and suffered a similar fate. Within three or four kilometres of Winson Green very few people survived the immediate effects of the detonation. Outside this range, and up to about seven or eight kilometres away, the collapse and destruction of most buildings trapped people in hundreds under fallen masonry. There were many deaths and severe injuries beyond counting. The air was full of flying objects, picked up by winds moving outwards from Winson Green at speeds which, even at ranges of four or five kilometres, approached 500 kilometres per hour. The wind drove along objects standing in its path like confetti. Motor cars and other vehicles were bowled over and over, carried tens and even hundreds of metres from where they were. People caught in the open were picked up, flung through the air and dashed against any solid object in their path. Roof tiles, pieces of masonry and any loose objects were projected through the air like missiles, smashing their way through obstructions and causing injury to many. At distances greater than seven or eight kilometres from the centre damage levels began to fall off, but even so all lightweight structures were blown over, roofs were blown off and higher masonry buildings suffered extensive damage. Large amounts of rubble and masonry fell into the streets and all windows were blown out, much of the glass being converted into missiles with much injury to people in the way.
A minor benefit of the blast-wave was that some of the innumerable fires started a few seconds earlier were blown out and did not rekindle. This was small mercy, however, compared with the even larger number of fires which were effectively fanned by the outward moving winds.
Birmingham airport, twelve kilometres from Winson Green, suffered relatively light damage, but wind speeds at the airport were of the order of 160 kilometres per hour and many aircraft lost wings and tailplanes or were turned on their sides by the blast-wave. Outside this range the effects of blast fell off rapidly, damage to buildings being confined to broken windows and shifted roof tiles.
The blast-wave had rolled outwards from the centre at something like the speed of sound, arriving at Birmingham airport approximately thirty seconds after the detonation of the weapon. Even at this point the roar of the explosion was stupendous, lasting for ten to fifteen seconds. The same roar was to be heard in London, approximately eight minutes later, as a rumbling, roaring noise from the direction in which the blinding flash of the fireball had been seen eight minutes earlier. Those in London with any knowledge of nuclear weapons were in no doubt as to what had happened.
Within one minute the stupendous activity of immediate damage from the detonation had ceased. The enormous mushroom cloud above the totally devastated centre of Birmingham had risen to a height of fifteen kilometres and had spread across a diameter of approximately twenty kilometres. It cast its shadow over a scene of extraordinary destruction, where everything was still except for the occasional crash of falling masonry and the crackle of multitudinous fires. Within a radius of five kilometres of Winson Green everything seemed to be on fire. Outside this area, to a range of about eight kilometres, hardly any building, or what survived of it, seemed to be free of a fire of some sort. Fires occurred less frequently outside this range though there were buildings on fire at ranges of up to fifteen kilometres. There were fires in towns as far away as Wolverhampton, Stourbridge, Halesowen, Solihull, Sutton Coldfield, Walsall and Brownhills.
The devastation within the centre of Birmingham was so intense that the road system had ceased to have any meaning, most roads having totally disappeared beneath the rubble of the buildings once standing along them. Outside this area, and to a range of five or six kilometres, all roads were totally blocked by fallen masonry. The only means of movement around the area was provided by the M5 and M6 motorways which encircle the centre of Birmingham. These roads, being wide and not hemmed in by buildings, remained relatively free of obstruction. The bridges along them had also survived remarkably well. Outside the motorway route the degree of devastation began to tail off, although most buildings still appeared to be unusable. Almost all roads were so littered with rubble that no immediate movement of vehicles was possible. The centres of Dudley, Walsall, Sutton Coldfield and Halesowen were impassable, though in these towns the outline of the road system was still visible and the overall extent of the damage, though still enormous, was considerably less than in the centre of Birmingham. Fires were prolific, particularly in commercial premises in high streets and commercial centres, holding large stocks of inflammable materials. In many places the gas distribution network had been broken and fires were being fed by escaping gas.