Short answers, pulled from the story.
The most accepted single figure for deaths during Operation Gomorrah is 37,000. The range from official records runs between 34,000 (from Hamburg police records) and 40,000. By the 1st of December 1943, there were 31,647 confirmed dead, but only 15,802 of those were identified from a body; in some shelters, the number of dead could only be estimated from ash on the floor.
Operation Gomorrah was a campaign of Allied air raids on Hamburg that began on the 24th of July 1943 and lasted eight days and seven nights. It was carried out by RAF Bomber Command, including RCAF, RAAF, and Polish Squadrons, and the USAAF Eighth Air Force. At the time it was the heaviest assault in the history of aerial warfare, with approximately 3,000 sorties flown and 9,000 tons of bombs dropped.
The firestorm was created when 787 RAF aircraft dropped concentrated bombing on working-class residential districts during an unusually dry period. Blockbuster bombs suppressed firefighting early in the raid, and the recall of Hanover's fire crews left Hamburg further undermanned. The fires merged and generated winds of up to 240 km/h and temperatures reaching 800 degrees Celsius, incinerating more than 8 square miles of the city. An estimated 18,474 people died that night, many from carbon monoxide poisoning in basement shelters.
Window was an early form of chaff: clouds of aluminium foil strips dropped by Pathfinder aircraft and the initial bomber stream to flood German radar screens with false returns. It was used for the first time during the first RAF raid on Hamburg on the night of 24-the 25th of July 1943. Its success was dramatic; only 12 aircraft were lost that night, 1.5% of the 791-strong force.
By August 1943-45 percent of all German fighters had been pulled back to the home front to defend against further raids. Heavy anti-aircraft guns in Germany were increased by over 25 percent. Anti-aircraft units eventually consumed 25 percent of all German ammunition for the remainder of the war. German armaments minister Albert Speer said in a 1977 interview that he had warned the Air Ministry that similar attacks on four or five other cities would cause Germany to collapse.
Hamburg was selected for several reasons. Its construction made its vulnerability "outstanding" according to planners, and it was Germany's second-largest city with more industrial targets than most other German cities. The Blohm and Voss U-boat shipyard and oil refineries in the Hamburg-Harburg area were high-priority strategic targets. Its position close to the coast and on a prominent river also made it easy for navigators to find from British bomber bases.