Area bombing of cities by the Royal Air Force and the United States Army Air Forces, and the firebombing of Japanese cities from late 1944, destroyed housing on a scale that emptied urban populations into the countryside. In Germany raids such as those on Hamburg in July 1943 and Dresden in February 1945 rendered whole cities uninhabitable within days; the United States Strategic Bombing Survey counted 3.6 million dwellings destroyed or heavily damaged and 7.5 million people made homeless, alongside state-organised evacuation schemes that moved children and non-essential civilians out of the cities. In Japan the incendiary raid on Tokyo of 9-10 March 1945 burned out fifteen square miles of the city in a night, and by the surrender about 30 per cent of the urban population had lost their homes; the government had already ordered the evacuation of schoolchildren and of large numbers of urban residents. The atomic bombings of Hiroshima and Nagasaki in August 1945 destroyed those cities outright. Much of this displacement was temporary, but it overlapped with the flight of civilians before advancing armies and, in Germany, with the expulsions of 1945 onward.
Allied air forces destroyed German and Japanese cities, and both governments evacuated urban populations under compulsion
The German census of May 1939 counted 69.3 million people within the pre-war Reich and the Japanese census of 1940 counted 73.1 million, a combined 142 million. The bombing acted on the urban share of these - roughly 45 million in German towns and cities and about 27 million in Japanese ones - so measured against urban populations alone the displacement share would be far higher.
The United States Strategic Bombing Survey estimated about 300,000 German civilians killed and 780,000 wounded, noting that German official statistics recorded 250,253 killed to January 1945 and that its own figures should be treated as a minimum; German research since has produced figures between 350,000 and 500,000. For Japan the Survey estimated about 806,000 civilian casualties including roughly 330,000 deaths, a figure that includes the atomic bombings; Japanese estimates for Hiroshima and Nagasaki alone, counting deaths from radiation injury by the end of 1945, are higher.
The scale of housing destruction and consequent homelessness is documented in the field surveys of city records carried out by the United States Strategic Bombing Survey in 1945-46.
Germany, Japan