Related: US Government website
Nuclear explosions can cause significant damage and casualties from blast, heat, and radiation but you can keep your family safe by knowing what to do and being prepared if it occurs.
A nuclear weapon is a device that uses a nuclear reaction to create an explosion.
Nuclear devices range from a small portable device carried by an individual to a weapon carried by a missile.
A nuclear explosion may occur with or without a few minutes warning.
Fallout is most dangerous in the first few hours after the detonation when it is giving off the highest levels of radiation. It takes time for fallout to arrive back to ground level, often more than 15 minutes for areas outside of the immediate blast damage zones. This is enough time for you to be able to prevent significant radiation exposure by following these simple steps:
(It appears they have updated the laughable, Duck and cover)