Imminent Missile Threat Preparedness

Information from Ready.gov 

A nuclear blast is an explosion with intense light and heat, a damaging pressure wave, and widespread radioactive material that can contaminate the air, water, and ground surfaces for miles around. A nuclear device can range from a weapon carried by an intercontinental missile, to a small portable nuclear device transported by an individual. All nuclear devices cause deadly effects when exploded.

Fact Sheet: Imminent Missile Threat or Nuclear Blast