From 30 miles, you'd be too busy tending to the third-degree flash burns on your exposed skin to be worrying about the cloud.

also a godzilla came out of it.

The issue is the explosion itself doesn't really tell the story. You can get a size using megatons, but its easier to just look at the destruction path to get a "real" idea.

The cloud is 7 times higher than Mount Everest... the image is taken from 100 miles away... the fireball itself was 5 miles wide... the single blast was 10 times ALL the explosives ever used in WWII combined, including Hiroshima and Nagasaki... imagine something really really big and this is way bigger.

the mushroom cloud in the photo above is rising from the clouds. look up and see how far away those are, now imagine a pillar of smoke and fire going all the way up there, and through them. also, the height involved should give you a relative idea as to how wide that pillar is. terrifying.

Well, to give you an idea, the top of the mushroom could reached up to 210,000 which is about 40 miles up. If you were 30 miles away, you'd have to crane your neck up about 50-odd degrees to see the top which makes it pretty big in my book. If you were 10 miles away, you'd have to lean waaaay back about 80-or so…

Castle Bravo was an accident. They expected a 4-6 MT yield but there was a runaway Lithium-7 reaction that increased the yield to 15 MT. The resulting shockwave endangered some forward observers, damaged the base camp, and the huge fallout plume contaminated a Japanese fishing boat; one of the crew eventually died.…

Nuclear bombs actually contribute to global cooling. Hence the term "nuclear winter".