how were Oppenheimer and Groves able to stand at ground zero right after the first atom bomb exploded without getting radiation poisoning?

Question

Speaking specifically to this picture

https://www.atomicarchive.com/history/trinity/afterwards.html

In: 685

Answer 1

That picture is from a few months later. They certainly would have been exposed to some radiation, but most of the contamination would have been blown away by the wind by then. Also, I don’t think they had as good of an understanding of fallout as we do now so probably wouldn’t have returned so soon these days.