On the night of 27 July, shortly before midnight, 787 RAF aircraft—74 Vickers Wellingtons, 116 Short Stirlings, 244 Handley Page Halifaxes and 353 Avro Lancasters— bombed Hamburg. The aiming points were the dense housing of the working-class districts of Billwärder, Borgfelde, Hamm, Hammerbrook, Hohenfelde and Rothenburgsort. The unusually dry and warm weather, the concentration of the bombing in one area and firefighting limitations due to blockbuster bombs used in the early part of the raid – and the recall of Hanover's firecrews to their own city – culminated in a firestorm. The tornadic fire created a huge inferno with winds of up to reaching temperatures of and altitudes in excess of , incinerating more than of the city. Asphalt streets burst into flame, and fuel oil from damaged and destroyed ships, barges and storage tanks spilled into the water of the canals and the harbour, causing them to ignite as well.