The beauty of the picture is misleading.
By the 1980s, atmospheric nuclear tests were passe. To find out the effects of a low yield nuclear blast on newer military hardware, the US military resorted to the next best thing: a large conventional explosion, codenamed Minor Scale.
How large? About 4.2 kilotons of TNT equivalent. Or roughly 30% of the Hiroshima bomb.
The resulting fireball may look like some wildflower at first sight, but the 19-meter long airplane in the foreground of the picture (just barely visible) helps put things into perspective.
Reassuringly, the US military stated that “Minor Scale” would not be followed by an even bigger, “Major Scale” test explosion.