Nuclear blasts set off a flash of light, a giant orange fireball, and shockwaves that can topple buildings. But a longer term threat comes in the minutes and hours after that explosion.
Nuclear explosions can produce clouds of radioactive dust and ash that disperse into the atmosphere — what's referred to as nuclear fallout. Exposure to this fallout can result in radiation poisoning, which can damage the body's cells and ultimately prove fatal.
The debris takes about 15 minutes after an explosion to reach ground level, so it's important to find shelter right away.
FEMA advises not to shelter in your vehicle, though. Cars' glass windows and metal frames make them too flimsy to protect you from nuclear fallout. Driving away is also futile, since it's tough to anticipate where the radiation will travel.
The one exception to this rule is ducking inside your car in an underground parking garage, which could provide an added layer of protection.
Read more: If a nuclear bomb explodes nearby, here's why you should never, ever get in a car