Flash burn victims from
(a) Hiroshima, showing pattern burns (i.e., the dark colored material pattern on the victims clothing absorbed the thermal energy and burned the skin), and
(b) Nagasaki, showing profile burns (i.e., burns around the light colored clothing that reflected the thermal energy).
Thermal / Burn injury
Burn casualties: mechanisms
Flash burns: absorption of thermal energy from the environment through exposed skin, with possible heating or ignition of clothing, (shown above)
Flame burns: caused by actual fires ignited in the environment, (not shown above)