[Publius6961]

Hardly anybody can get their minds around an explosion 1,000 X Hiroshima bomb.

But still most of the ignorant tend to overestimate the extent of the damage. By a whole bunch.

[Cyber Liberty]

It's all in how the damage is intended. It can be pretty bad, if wiping out everything in a city is what you want. However, that's militarily useless, I would think, so the blasts are designed to do closer, more intense damage.

You don't want to be within 30 miles of a "Castle Bravo" 15 megaton firecracker. At optimum blast height, that distance left islands burnt to a crisp before the shock wave blew the burning trees out to sea.