[Dan Evans]

We may need to rethink a LOT of policies--such as the desire to stuff as many people as humanly possible into close quarters and call the result "urban planning."

I agree. With the technology we have, cities are obsolete. Dispersal of the population is a good thing that is being disparaged as "suburban sprawl" by urban politicians who see it as a shrinking tax base.

But the fires that DO start will not get put out, and will continue dumping secondary activation products downwind,

There has never been a nuclear ground burst in city before so we can only speculate. Anything shielded by a building would not catch fire and would receive a lot less blast damage. It would not be a firestorm.

[Poohbah]

There has never been a nuclear ground burst in city before so we can only speculate. Anything shielded by a building would not catch fire and would receive a lot less blast damage. It would not be a firestorm.

Actually, the modern architectural style (glass facades that are very reflective in the SWIR and LWIR bands) would probably wind up igniting a bunch of fires--the initial thermal pulse would get reflected every which way (before those windows blew in/out) and hit just about every flammable surface available. Instant fires...the lack of a major blast wave would actually tend to keep those fires lit.