Fallout severity and extent depends on several complex factors:
Type of nuclear weapon used. Some are designed to minimize fallout (fusion or H-bombs), others are designed to maximize it (dirty bombs)
Height of detonation. Closer to the ground generally means less fallout. Higher up means more fallout and a wider area EMP effect.
Local weather conditions and geography. As another commenter has pointed out, wind conditions and proximity to a river valley can drastically increase how far the fallout will spread in a certain direction.
How many different bombs are used and wether there is nuclear retaliation. MAD is real policy for the US and Russia.
TL;DR: a nuclear bomb spells bad news no matter what the variables are. Pray it never happens for real and that at worst it is only a fake scare event.
Fallout severity and extent depends on several complex factors:
TL;DR: a nuclear bomb spells bad news no matter what the variables are. Pray it never happens for real and that at worst it is only a fake scare event.