ハンブルグを10日間爆撃し続けたゴモラ作戦から80年。その詳細を英語で

Alan Allport @Alan_Allport

Today marks the 80th anniversary of the start of Operation GOMORRAH, the 10-day Anglo-American campaign of day and night bombing of Hamburg. It’s an anniversary that ought to be remembered and mostly won’t be. A thread. pic.twitter.com/VYdABT2sKx

拡大

Alan Allport @Alan_Allport

By July 1943, RAF Bomber Command, after years of delays and failures, had at last built up a force of 4-engine heavy bombers strong enough to be able to carry out truly damaging raids on German cities.

Alan Allport @Alan_Allport

This force had been used in a sustained way for the first time against the towns of the Ruhr, most of all Essen with its famous Krupps Works, during spring 1943. These were ‘area’ bombing night raids using a mixture of high-explosive and incendiary bombs.

Alan Allport @Alan_Allport

‘Area’ bombing was conducted not directly against industrial targets (often on the fringes of cities) but against the dense concentrations of working-class tenement housing at the center of most German cities.

Alan Allport @Alan_Allport

The theory of area bombing was that the destruction of residential areas would indirectly disrupt industrial output by killing and ‘dehousing’ workers, and also that it might reduce German civilian morale to breaking point – though the latter aim was not universally agreed upon.

Alan Allport @Alan_Allport

Some RAF leaders saw night area bombing as a regrettable necessity until such time as British bombers could again fly by day (ruled out until the German day fighter force was eliminated) and/or aiming methods became accurate enough to hit precise industrial targets.

Alan Allport @Alan_Allport

This view was not however held by the AOC-in-C of Bomber Command since Feb 1942, Arthur Harris. He was not responsible for the area bombing policy (his boss the Chief of the Air Staff Sir Charles Portal was) but he had become a true believer.

Alan Allport @Alan_Allport

Harris had had his eye on Hamburg for some time. In late May 1943 he wrote to his Group commanders that “The total destruction of this city would achieve immeasurable results in reducing the industrial capacity of the enemy’s war machine.”

Alan Allport @Alan_Allport

The technical problem with Hamburg was that it lay outside the range of ‘Oboe’, the new radio-transponder targeting system which had been used to such dramatic effect in the raids on the Ruhr.

Alan Allport @Alan_Allport

However, Bomber Command also had a new air-to-ground radar set, H2S, which could be carried in a heavy bomber and gave a rough visual image of the landmarks below, allowing navigation to the target.

Alan Allport @Alan_Allport

H2S worked best when the target had clearly distinctive physical features, and the broad Elbe river and Hamburg’s dock basin were ideal for this.

Alan Allport @Alan_Allport

Bomber Command also wanted to try out ‘WINDOW’, now known as chaff, a metallic anti-radar scrambling system which it was hoped would neutralize the German nightfighter and Flak defenses.

Alan Allport @Alan_Allport

GOMORRAH opened on the night of July 24/25 with a mass raid which did widespread damage in the central and northwestern areas of Hamburg, killing about 1,500 people. But the effect was limited due to a seven-mile ‘creep-back’ from the aiming point.

Alan Allport @Alan_Allport

Creep-back was a phenomenon by which bombers dropped their payloads earlier and earlier along the line of approach to the target. It meant that the bombs were less densely concentrated than they were intended to be, reducing their effectiveness.

Alan Allport @Alan_Allport

On July 25 and 26 the USAAF 8th Air Force conducted daylight raids against Hamburg – GOMORRAH was a rare occasion in 1943 of cooperation between the two allied bombing forces. They attacked the dock and shipyard areas rather than housing.

Alan Allport @Alan_Allport

Neither American raid was especially precise and the damage was limited. As was often the case in these early raids, the US day bombers suffered heavily from losses caused by German single-engine fighter interceptors.

Alan Allport @Alan_Allport

On the night of July 27/28 the RAF heavy bombers returned. This was the night of Hamburg’s notorious ‘firestorm.’ Most of the 2,326 tons of bombs crashed down into a rectangle four square miles in area. There was almost no creep-back. Concentration was achieved in time and space.

Alan Allport @Alan_Allport

From a technical point of view it was a bravura performance. Also, it had been a hot July, with low humidity and no rain for some time. Everything in Hamburg was very dry.

Alan Allport @Alan_Allport

Hammerbrook, Hamm, and Borgfelde, the districts of the city which were hit, were composed of cramped, six-story nineteenth century tenement blocks divided by narrow streets and alleyways. Shipyard workers and their families lived there. There were a lot of children.

Alan Allport @Alan_Allport

The high explosive ordnance dropped by the first bombers smashed in doors, windows, and roofs, exposing combustible furniture and timber joists and floors for the incendiaries to ignite.

Alan Allport @Alan_Allport

The Air Ministry’s RE8 research department had been intrigued for some time about how under the right conditions of temperature and wind speed, small individual fires might be encouraged to merge together to form a single uninterrupted blaze sucking in everything flammable.

Alan Allport @Alan_Allport

A density of 25,000 four-pound incendiaries per square mile, complemented by heavier phosphorus and benzol gel bombs to reach more inaccessible nooks, was calculated to be the optimum formula to provoke this.

Alan Allport @Alan_Allport

Previous attempts to create such a ‘firestorm’ on a large scale had been foiled by inaccurate navigation, bad target marking, scattered bombing patterns, bad weather, or efficient German countermeasures. Now, RE8’s tireless and meticulous efforts were finally going to pay off.

Alan Allport @Alan_Allport

The firestorm began at 1.20am on Wednesday morning, reached its crescendo at about 3am and began to ebb about one-and-a-half hours later when there was nothing left to burn. During that time the best modern estimates suggest that 18,400 people were killed in Hamburg.