I was reading through the nuclear threat page on dhs' website:
If there is no warning
1. Quickly assess the situation. (you have roughly .000161046 seconds @ 30miles away, quick now!
2. Consider if you can get out of the area or if it would be better to go inside a building to limit the amount of radioactive material you are exposed to. (Because the building will soon erupt into flames and then be knocked down by the shock wave)
3. If you take shelter go as far below ground as possible, close windows and doors, turn off air conditioners, heaters or other ventilation systems. Stay where you are, watch TV, listen to the radio, or check the Internet for official news as it becomes available. (If you have windows in your bomb shelter you made it wrong.) (Also that tv and radio and comp that work on EM radiation, yeah not working at this time.)
4. To limit the amount of radiation you are exposed to, think about shielding, distance and time.
* Shielding: If you have a thick shield between yourself and the radioactive materials more of the radiation will be absorbed, and you will be exposed to less. (Because everyone has a slab of heavy metal laying around, ideally lead)
* Distance: The farther away you are away from the blast and the fallout the lower your exposure. (Really? I thought I should run closer!)
* Time: Minimizing time spent exposed will also reduce your risk. (And without said bomb shelter or slab of lead, our options to not being exposed are?)
If you think you have been exposed to radiation, take off your clothes and wash as soon as possible. (cause radiation exposure just washes off kids!)
Bottom line is if there is a nuclear weapon detonated close to you you're ****ed, and there;'s not a damn thing you can do about it. That why it's the only real WMD.