Bombing of Hiroshima
On August 6, 1945, three B-29 bombers took off from Tinian, which is a small island in the Marianas. Colonel Paul Tibbets piloted the aircraft nicknamed Enola Gay, which was armed with the atomic bomb, while two other aircrafts were also involved in the mission and in charge of instrumentation and photography. Three other planes served as weather scouts for the cities of Hiroshima, Kokura, and Nagasaki. The planes flew separately on the mission, but rendezvoused at the island of Iwo Jima before heading towards the primary target of Hiroshima.
Japanese radar operators first detected the weather scout plane over the city of Hiroshima. Bomb warnings were sent out, but officials decided the coast was clear because the plane turned around after seeing clear weather conditions. When Enola Gay and the two accompanying planes approached the city, another air raid alert was sent out for many large cities, but the radar operator in Hiroshima determined that there were only a few planes approaching, the alert was canceled. It was assumed that these few planes, along with the weather scout plane were only on a reconnaissance mission, and people were not advised to seek bomb shelters (Trinity Atomic Web Site). Because of this determination, Tibbets was able to fly over the city with relative ease. The bomb was dropped at approximately 8:15 AM over the Aioi Bridge, which was the intended target. The bomb, nicknamed “Little Boy”, exploded at 1,900 feet above the city, and narrowly missed the target by approximately 800 feet. The bomb’s explosion completely destroyed everything within a one-mile radius of the hypocenter. A firestorm sprang up and spread the destruction to a radius of about three miles. Estimates range from 60,000 to 80,000 deaths immediately following the explosion, with many more later on due to exposure to radiation.
Japanese radar operators first detected the weather scout plane over the city of Hiroshima. Bomb warnings were sent out, but officials decided the coast was clear because the plane turned around after seeing clear weather conditions. When Enola Gay and the two accompanying planes approached the city, another air raid alert was sent out for many large cities, but the radar operator in Hiroshima determined that there were only a few planes approaching, the alert was canceled. It was assumed that these few planes, along with the weather scout plane were only on a reconnaissance mission, and people were not advised to seek bomb shelters (Trinity Atomic Web Site). Because of this determination, Tibbets was able to fly over the city with relative ease. The bomb was dropped at approximately 8:15 AM over the Aioi Bridge, which was the intended target. The bomb, nicknamed “Little Boy”, exploded at 1,900 feet above the city, and narrowly missed the target by approximately 800 feet. The bomb’s explosion completely destroyed everything within a one-mile radius of the hypocenter. A firestorm sprang up and spread the destruction to a radius of about three miles. Estimates range from 60,000 to 80,000 deaths immediately following the explosion, with many more later on due to exposure to radiation.
The city’s topography had a large impact on the explosion. Hiroshima is located on a flat delta of the Ota River, which flows into Hiroshima Bay. This flat parcel of land is between tall hills that contained and reinforced the explosion of the bomb to the city. This, combined with the ease that the fires were able to spread throughout the city, caused extensive structural damage. The hills to the northwest of the city prevented damage from extending in that direction.
Diagram of the city of Hiroshima and extent and severity of damage draped over the DEM. The cross-hatched area shows very severe damage from the blast and fires and extends one mile from the hypocenter. Other areas of less-severe damage extend up to three miles from the hypocenter.
DEM Source: USGS.
Image Source: http://www.allworldwars.com/Photographs-of-the-atomic-bombings-of-Hiroshima-and-Nagasaki.html