The wind velocity of the blast was 170 meters per second at the point 1 kilometer away from the hypocenter. If you compare it with the wind velocity of a maximum typhoon of 80 meters per second at most, you can understand how strong and how destructive it was. The instantaneous pressure was estimated to be 6.7 to 10 tons per 1 square meter just under the hypocenter.
The blast destroyed every building standing in the vicinity of the hypocenter and reached a distance of about 3.7 kilometers away from the hypocenter in about 10 seconds after the atomic bombing, and of about 11 kilometers in 30 seconds. The power finally decreased in the vicinity of this point, however, an area even as far as 15 kilometers away from the hypocenter seemed to be affected by this destructive power.
