Several days before dropping the first and second only nuclear bombs ever used, leaflets were dropped from B-29 Superfortresses for the populace of Japan to read and acknowledge. How effective were these warnings in saving the citizens below from their impending doom? Did many take heed, or did they largely go unnoticed, as another scare tactic by the Allied forces?
The leaflets did not warn about atomic attacks and were not dropped on Hiroshima or Nagasaki; there was no actionable warning. This is a persistent Internet myth, my absolute least favorite of many such myths about the atomic bomb (because it exists solely to make Americans feel better about the bombings). Brief discussion here, long discussion here, both with linked reports, created at the time by the people in charge of the leaflet campaign, that make it quite clear that the only warning leaflets about the atomic bomb were dropped after the atomic bombs. The author of the CIA website article has totally disclaimed the caption that implies that LeMay leaflets were dropped on Hiroshima.
Hi, there have been several posts on these leaflets. Check out the following answers from /u/restricteddata:
Did the US warn civilians in Hiroshima about the atomic bomb attack? - note also the link to his blogpost, which is also linked at the bottom of the "leaflet" link you provided
more discussion in response to a followup question in Why did the U.S. decide to bomb civilian cities with atomic bombs rather than military targets during WWII?
a critical look at claims on a CIA webpage in Were warning leaflets dropped on Hiroshima and Nagasaki before the atomic bombs were dropped there?
on evacuation in Why didn't many people evacuate Hiroshima and Nagasaki after the warning leaflets were dropped?