[Dan Evans]

According to your table, a strip of real estate about half a mile wide and twelve miles long would be contaminated with radiation levels that would be fatal in about one hour if they were standing outside. If they move to the lower levels of multi-story buildings and went to interior rooms away from the broken windows and dust they would be receiving a much lower dose.

So how many people would that affect? Figure about 35,000 people per sq mi times 7.8 sq mi. That's 273,000 thousand people that would need to be evacuated in a few days.

It could be done.

[Poohbah]

Your problem is that you're presuming that everyone will behave rationally when they're immediately downwind of a surface burst.