At a distance of 40-45 miles, a person would have a maximum of 3 hours after the rain began to find shelter. Significantly smaller doses of radiation will make people seriously ill. Therefore, the prospects for survival of people immediately downwind of the burst point would be slim unless they could be sheltered or evacuated. To date, those are the only cases of the use of nuclear weapons for war, but the reality is that there are approximately 12,700 warheads left in the world today.
When a nuclear weapon is surrounded only by air, lethal explosions and thermal effects increase proportionately much more rapidly than the lethal effects of radiation as explosive performance increases. A Faraday cage offers no protection against the effects of EMP unless the mesh is designed to have holes no greater than the smallest wavelength emitted by a nuclear explosion. If you somehow survive all of that, you still have to deal with radiation poisoning and nuclear consequences. Large nuclear weapons detonated at high altitude also cause geomagnetically induced current in very long electrical conductors.
This form of radioactive contamination is known as nuclear fallout and represents the primary risk of exposure to ionizing radiation for a large nuclear weapon. In a nuclear explosion, injury or death can occur as a result of the explosion itself or as a result of debris thrown by the explosion. However, for more information on the current state of nuclear weapons in the world, including the scale of bombs, you can visit the Nuclear Notebook in the Bulletin of Atomic Scientists. Studies on the total effect of nuclear explosions on the ozone layer have been, at least tentatively, exonerating following initial discouraging findings.
Heat and debris in the air created by a nuclear explosion can cause rain; debris is believed to do this by acting as condensation cores for clouds. Intense thermal radiation at the hypocenter forms a nuclear fireball that, if the explosion is low enough in altitude, is often associated with a mushroom-shaped cloud. In 1942, there was some initial speculation among scientists who developed the first nuclear weapons in the Manhattan Project that a large enough nuclear explosion could ignite the Earth's atmosphere. Nuclear weapons emit large amounts of thermal radiation in the form of visible, infrared and ultraviolet light, to which the atmosphere is largely transparent.
A nuclear explosion, caused by the explosion of a nuclear bomb (sometimes called nuclear detonation), involves the joining or splitting of atoms (called fusion and fission) to produce an intense pulse or wave of heat, light, air pressure, and radiation. But in the following video, the ASAPScience team analyzes the science of nuclear bombs to predict the likelihood that you will survive.