NYC releases PSA for what to do in case of nuclear attack

I don't think that's case at all. If you're dealing with fallout, the radiation decreases with time. Waiting 24 hours is better than not waiting at all, but I've seen charts and I'm under the impression that's only enough time for the radiation to decrease by ~50%, which could still be very lethal.

https://external-content.duckduckgo.com/iu/?u=https%3A%2F%2F...

Bunkers are all about surviving indirect blasts and protecting from radiation exposure. If you have a deep enough underground bunker, you largely protect yourself from a “direct blast,” but if a weapon burrowed anywhere near your bunker and detonated it’s good night. You’d also need nation-scale resources to build a bunker deep enough, and have air, water, vapor barriers, etc.

Now most of NORAD is at another, completely unsheltered facility because missiles are so accurate that no protection matters.

Cheyenne exists mainly for lesser threats than general nuclear exchanges.

Not necessarily. Having "a few nukes" means they will almost certainty used against civilian population centers (coutervalue), because that results in more destruction per nuke. If you have more nukes, it may be sufficiently deterring to only attack military targets (couterforce) and kill fewer civilians.

https://journals.sagepub.com/doi/pdf/10.2968/057004008:

> The first scenario that NRDC ran involved a counterforce attack against Russian nuclear forces. They believed this scenario to be close to the one fabricated by Stratcom. Using the most comprehensive levels of targeting for Russian aviation and naval sites, the total number of warheads required by the first NRDC plan was 1,289... The result of the “attack” as detailed in the report... Then the fallout would descend, creating lethal conditions over an area larger than 775,000 square kilometers... casualties would be between 11 and 17 million, of which eight to 12 million would be fatalities.

> But what would happen if the United States drastically reduced the number of weapons in its arsenal and abandoned the pretense that one kind of nuclear targeting is more morally acceptable than another? How many nuclear weapons is enough to deter a nuclear attack on the United States, which, according to the NRDC report, is arguably the only reason for continuing to possess nuclear weapons at all?

> To illustrate this, NRDC ran nuclear attack scenarios on Russian cities using either 150 single-warhead, silo-based ICBMs or 192 single-warhead, submarine-launched ballistic missiles (SLBM's), essentially the load aboard a single fully loaded Trident submarine. The results from either scenario, each using less than 3 percent of current U.S. nuclear forces, resulted in more than 50 million casualties [computed casualties totaled 52 million people, including 49 million deaths].