Not sure I would agree with that - a single 800kt detonation over Manhattan looks pretty bad to me and a realistic attack would probably have had many tens of warheads used.
Here is a rather jolly 1980's BBC documentary that spends a lot of time looking at the effects of a single 1Mt warhead on London:
Well when I mean pretty underwhelming I mean that I kinda expected a nuke to take out the entirety of New York + a big chunk of the east coast. I mean these are the weapons of doom, right? The weapons that will end the world?
And yet if you are just 30 miles from the target the first time you are going to notice is when you turn on the TV.
Keep in mind that at the height of the Cold War, both the US and USSR had thousands of nuclear warheads. A single nuke might not be a civilization-destroying weapon, but a carpet bombing of nukes sure is.
Well, with a single 25Mt ground burst in New York and the wind in the right direction Boston would be getting 1000 rads/hour - which is not going to be good if you are not in some kind of protected area.
Mind you, although the Soviets did have 25Mt warheads on ICBMs they were targeted on key bunkers - Cheyenne Mountain, Raven Rock Mountain etc.
Not sure I would agree with that - a single 800kt detonation over Manhattan looks pretty bad to me and a realistic attack would probably have had many tens of warheads used.
Here is a rather jolly 1980's BBC documentary that spends a lot of time looking at the effects of a single 1Mt warhead on London:
https://www.youtube.com/watch?v=vejorfkdgwU
Of course, it does finish by noting that a real attack would have multiple ground and air bursts.
[NB UK("pretty bad") == NonUK("utterly appalling")]