Source: Planning Guidance for Response to a Nuclear Detonation, Second edition, 6/2010 (PDF - 2.62 MB) (National Security Staff, Interagency Policy Coordination Subcommittee for Preparedness & Response to Radiological and Nuclear Threats, page 25)
Original Source: Pictures of World War II, U.S. National Archives & Records Administration, 77-MDH-6.55b
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