First thing: I don't know if it's the right stack to ask this question, so I'm sorry if it's not.
I'm writing an adventure for an apocalyptic RPG session. One point of the plot is a detonation of 100 kt nuclear device in Salt Lake City. At that moment I want my players to be somewhere along the Lincoln Highway (80) in the roadside motel/bar/gas station. This place don't have to exist in real life but I want to place it in realistic location for such enterprise. I was thinking about the junction with road 65 (Google maps shows Mountain Dell Golf Course nearby if you want to see where it is. I'm not from US so I don't know if the numbers of the roads give the exact position). I want my players to be aware of the explosion as soon as it happens but they will probably not be able to see the mushroom cloud because of the mountains. I plant the nuke to be W-76 which is 100 kt, that will give us a 1km high mushroom cloud, but the mountains between the highway and SLC are taller. My question is: what signs of the detonation could be seen/heard? Maybe they should learn about the detonation form some other source? Or maybe I should change the location of the motel? My goal is for them to be aware of the incident and to stay put for at least 30-60 min until the next plot point unravels.