"Ashes" ...time to run this one again.

If you are anywhere within 50 miles of a multi warhead hit on a major city read no further. You are dead...period.

This from direct blast injury from being buried under burning wreckage asphyxiation as all the air is sucked up by the multiple fire storms that will soon congeal into a vast regional blaze.

If you are 100 miles away your chances would be 1 in 40. This for immediate survival. Your dangers will be break down of order, and the radioactive frontal waves from the firestorms that will in a few hours reach you.

Your life expectancy increases the farther away you go.

If I 'had' to be in a state that was hit I'd want to be a minimum of 200+ miles from the many ground zeros. Even then I'd be on the move to get further away especially if the winds were in my direction. We must remember if a nuclear exchange between the major powers happens it will not be 'one' mere bomb from a plane.

This the cold war stereotype of attack.

Whole squadrons of ICBMs will be assigned to hundreds of individual military industrial financial, and yes 'cultural' targets. This is intentional.

Understand this kind war for both sides is to the total destruction, and death of your enemies. The idea is to utterly destroy not just the military economic, and political centers, but the whole complete culture. The traditions histories peoples. To wipe you, and the memory of you from the face of the Earth.

That is the true purpose of Nuclear war.

That said you must know that each target will have 10 to as many as 50+ warheads hit it. Especially if a military area or political center. For example. After the cold war when the Soviet achieves were for a short time open to western scholars we discovered that the Pentagon alone had 30+ warheads of varying strength targeted on it. NYC in excess of 300.

One has to think in such terrible terms. Imagine the un-imaginable if you even have the slightest hope you're going to survive.

Bottom line...

If you can see it or hear it you are immediately dead or dead in hours.

However a terror nuke is another matter.

This may be "just" the spreading of radioactive dust over a distance of 5 to 20 miles. That or a low yield radiological explosions at several regional locations. Each with perhaps a quarter+ the force of the Hiroshima bomb.

These are "survivable" for many if circumstance is with us.

If somewhat favorable conditions are met. Perhaps half the population of the target city (s)  'may' live. If not then just a fraction may "exist" with traumatized shortened post strike lives. This of course because of blast injuries emotional scaring's, and radiation induced cancers in the next 10 to 30 years.

That's it in a nutshell for a "Terror Bomb (s)".

Things of course can vary widely because of type of warheads weather time of day social resilience, and local ground conditions.

...That said "Who wants Pie!"