In late July 1943, the city of Hamburg was bombed during Operation Gomorrah by combined RAF and USAAF strategic bomber forces. Four major raids were carried out in the span of 10 days, of which the most notable, on the night of 27–28 July, created a devastating firestorm effect similar to Dresden's, killing an estimated 18,474 people. The death toll for that night is included in the overall estimated total of 37,000 for the series of raids. Two-thirds of the remaining population reportedly fled the city after the raids.