https://nuke.fas.org/guide/usa/napb-90/annexb.pdf
http://www.radmeters4u.com/list.htm
https://commons.wikimedia.org/wiki/File:Fallout_map_USA_(FEM...
https://www.fema.gov/sites/default/files/documents/fema_plan...
It's based on this video from Prof. Brian Toon: https://www.youtube.com/watch?v=AzwHbHlK5kI, who to my knowledge has done the most in depth studies on it.
On a more granular scale, Nukemaps [2], which probably everyone knows by now, shows the area of fallout for a given blast based on real-time wind data.
[1] https://www.icanw.org/new_study_on_us_russia_nuclear_war
NARAC monitors and predicts the spread of wind/water carried nuclear, biological, chemical, and other hazardous materials in emergencies. You can see videos of recent responses on their website; the highest profile one was probably the Fukushima disaster (if you remember the various evacuation recommendations, NARAC guided the US ones). Here are some more: https://narac.llnl.gov/about/timeline, including the Eyjafjallajökull volcano.
They run in some of their own (comparatively) smaller clusters for quick turnaround simulations, as well as on LLNL’s bigger HPC systems (https://hpc.llnl.gov/hardware/compute-platforms) when there’s a need.
This is a serious question. I'm asking because I find the hobby-level interest in nuclear war kind of offensive. It trivializes a profound threat to humanity.