Damage by the Heat Rays

Within 0.3 seconds of detonation,
the fireball high in the air grew
to a diameter of more than 200 meters.
The temperature on the surface was 7,000 degrees C.
The heat rays released by that fireball
devastated the people and things below.

1951,1952, from an American film of a nuclear weapon tests
Conditions in Hiroshima after the Bombing (American military material)
Looking at the List