:It's a college town, and to my knowledge there is nothing there that would make it a wartime target. Knowning that Lawrence was hit changes a lot, though; before Gray's report, I think the general assumption was that only the real big cities were hit. If Lawrence was hit, though, that means a hundred other smaller cities across the U.S. could also have been targets.
Not to launch into too much speculation here, but that opens up some interesting possibilities. If the people of Jericho could see a mushroom cloud over Denver, then they would surely see one over Colorado Springs (the home of NORAD) and Pueblo. Wichita (which is about as far from Jericho as Denver is) might also have been a target, since its population is more than three times that of Lawrence. As has been mentioned before, Denver is not visible from western Colorado (nor are there any real mountains anywhere in the vicinity). If the bad guys unleashed Tsar Bomba upon the city of Denver, then maybe, but Gray said the NYC bomb they intercepted was only 20 kilotons.
A possible answer to this is that the mushroom cloud seen in the first episode could have been over one of the smaller cities closer to the Kansas border, say Limon or Sterling. There are no towns between Denver and Kansas that have a population of more than fifty or sixty thousand. But if Lawrence was hit....
It seems like those in Jericho would be able to visually estimate the distance, though, so I'm more inclined to chalk it up to "hey, it's just a tv show!". But it does remind us that the people of Jericho (and we at home) don't know anything for sure, which is one thing that seems pretty realistically done in the show.
And I was going to say something about The Day After as well, but 199.79.222.119 beat me to it. Must... type... faster...!  ‹ ✆|✍ ›