If a nuclear weapon is about to explode, here are 17 things you can do (2024)

Still, world leaders are taking the threat seriously. In case the worst happens, there are easy tips to remember to minimise the risk.

"Fallout casualties are entirely preventable," Brooke Buddemeier, a health physicist and expert on radiation and emergency preparedness at Lawrence Livermore National Laboratory, told Insider in 2018.

"Knowing what to do after an event like this can literally save hundreds of thousands of people from radiation illness or fatalities."

Here are 17 tips to best protect yourself in case of an impact.

A flash, a burst, and a blast

According to FEMA, here are six important stages during a nuclear weapon impact:

1. A bright flash caused by a huge fireball, which can cause temporary blindness
2. A blast wave, which can flatten buildings and cause serious injury and death. This wave can take several seconds to reach you.
3. A pulse of nuclear radiation.
4. Fire and heat, which can cause out-of-control fires.
5. An electromagnetic pulse, which can disable devices for miles around.
6. Radioactive fallout, contaminated particles kicked into the air by the blast. It can take up to 15 minutes to arrive. High-altitude winds can make it sprinkle over hundreds of square miles, though it's most intense near the blast site.

Nuclear weapons are deadly, and after an impact on a major city tens to hundreds of thousands would likely die.

But the worst destruction, where the chances of survival are least likely, is confined to a "severe damage zone," Buddemeier said. For a 10-kiloton blast — equivalent to two-thirds of the Hiroshima bomb blast — that's about a half-mile radius.

There are ways to enhance your chance of survival in the unlikely scenario a nuclear bomb were to hit your town.

"There were survivors in Hiroshima within 300 meters [900 ft] of the epicenter," Buddemeier said.

How to prepare

The American Red Cross advises that you build an emergency preparedness kit. This is a kit that should keep you going in case of any emergency. It includes water, food, flashlight, medication, and other items (more information can be found here).

It's also good practice to look out for fallout shelters available in your community and to build a plan for your family in case of disaster. Lastly, learn ahead of time which channels to use to get notifications from official sources, per the Red Cross.

What to do if you get a notification of imminent attack

If you receive notification of an imminent attack, your first priority is to seek shelter that will protect you both from bodily harm from the blast and from the radiation in the fallout that will follow.

If you're driving, pull over, get out, and make your way into a building, Buddemeier said.

Seek shelter indoors, preferably underground and in a brick or concrete building, per the Red Cross and FEMA.

Go as far underground as possible, per the Red Cross and FEMA. If that's not possible, try to stay in the center of the building, for example in a stairwell.

The deeper and lower in the building you can get and the farther from windows (which can shatter), doors (which can fly open), and exterior walls (which can cave in), the better your odds.

"I think of the same kinds of things that we do for tornadoes," Buddemeier said.

Don't look at the fireball, as the light could temporary blind you, per FEMA.

Stay tuned for more instructions. Mobile networks may be interrupted, but radios should still function, per FEMA.

Humans and pets should stay inside for at least 24 hours or until instructed otherwise by authorities, per the Red Cross.

What to do if you're outside when the blast hits

If you're outside, your first priority is to shelter from the blast wave.Take cover behind anything that could protect you and lay flat on the ground and cover your head, per the Red Cross.

Don't assume the blast has passed you — it could take up to 30 seconds for the wave to reach you, per the Red Cross.

After the blast wave passes, you want to limit exposure to radiation.

If you're still outside, cover your mouth with a cloth or a towel, which can reduce the amount of radioactive fallout you breathe in, per the Red Cross.

Take shelter as soon as possible, regardless of how far you are from the impact. Radioactive fallout can travel hundreds of miles, per the Red Cross.

As soon as you are safely inside, remove the outer layer of your clothing.

What to do once you've found shelter

If you were outside, you want to get the fallout as far away from your body as possible.

Too much exposure over a short time can damage the body enough to limit its ability to fix itself, fight infection, and perform other functions, leading to a dangerous condition called acute radiation sickness.

Typically, about 750 millisieverts of exposure within several hours can make a person sick. This is roughly 100 times the amount of natural and medical radiation that an average American receives each year. A 10-kiloton blast can deliver this much exposure within a radius of about a mile.

Removing your outer layer of clothing can reduce the amount of contamination from fallout by up to 90%, per the Red Cross.

If possible to do so safely, put all the contaminated clothing into a plastic bag that you keep far away from others and pets — the clothes may still be emitting radiation.

Wash your hair and skin with water and lots of soap and shampoo. Do not scratch the skin and do not use conditioner, which would bind any the radioactive material to your hair, per the Red Cross.

Gently blow your nose and wash out your ears, where contaminated dirt may be trapped, per the Red Cross.

A shower is best. If that's not available, a wet cloth wash will still help, provided the cloth hasn't been outside, per FEMA.

If your pet was outdoors, they could also be covered in fallout which could expose you and them. Gently brush your pet's coat then wash then with soap and water, per FEMA.

If you can, close windows and fireplaces, turn off fans, air conditioners, and forced-air heating units, per the Red Cross.

Be prepared to shelter

It's best to hunker down in your blast shelter if you're unsure whether it's safe to move.

At this point, fires and obstructive debris are likely to be widespread, Buddemeier said.

Eat and drink only packaged food items or items that were inside a building, per FEMA.

Care for your emotional wellbeing and the wellbeing of your children. Focus on positive actions you can take, limit exposure of children to media reports that can be scary, remember to eat and drink, and be patient with others, per the Red Cross.

"The most important thing in both cases is to be inside when the event occurs, either when the detonation occurs or when the fallout arrives," Buddemeier said.

This article was first published in January 2018 and has been updated to reflect recent developments. Dave Mosher contributed to the earlier version of the story.