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How Far Does Nuclear Fallout Travel?

With the state of the world today, people are wondering now more than ever how to keep themselves safe, and how to build a bomb shelter for protection in the event of a nuclear fallout. With rising tensions all over the world, it’s important to understand nuclear explosions, and how to behave in the case one happens. If you’ve ever wondered, “how far does nuclear fallout travel?” you’ll know by the end of this article.

How far does nuclear fallout travel?

Keep reading for information about the effects of nuclear explosions, and how to build a bomb shelter.

Nuclear Explosion

A nuclear explosion is what results from the detonation of a nuclear device. The explosion immediately causes a large fireball, which vaporizes everything within it and in surrounding proximity, and pushes it upward into the familiar mushroom cloud you might remember from your history class on Hiroshima and Nagasaki. This could result both from an intentional attack, and an accidental cause, like Chernobyl. Either way it’s important to be ready by learning how to build a bomb shelter.

Immediate Local Impact

When it comes to the question, “how far does nuclear fallout travel?” nuclear explosions have a devastating impact on both local communities and globally. Obviously, populations that live in proximity to an explosion are impacted more heavily and sooner than those who live farther away, who could feel the effects in the following months, years, and even decades.

Experts have estimated that if an American city were subject to a nuclear explosion of 100 weapons of one-megaton fission yield, twenty percent of the American people would immediately lose their lives from immediate local impact, including the blast, heat, light, shock wave, and radiation from the explosion.

This does not include the damage that would quickly be caused by fires, neglected injuries, debilitated emergency services, and compromised infrastructure. Depending on the design of the device and the location of the detonation, the explosion would cause immediate catastrophic damage both to surrounding infrastructure, human life, and the environment.

How far does nuclear fallout travel? When it comes to the side effects of nuclear fallout, five to 50 miles. Typical injuries of survivors close to the explosion who were unable to take shelter in bomb shelters include severe burns (up to third-degree burns even five miles away), injuries caused from debris thrown around by the shock wave, temporary blindness from the flash of light from the explosion (which can impact people over 50 miles away), and even permanently burning the retina.

A warning sign for nuclear fallout

The kind of damage most closely associated to nuclear explosions, however, is that of harmful radiation. Within the mushroom cloud that billows above the explosion, radioactive elements from the nuclear device mixes with other vaporized elements like earth, water, and air, and eventually condenses into small particles that float in the atmosphere. This radioactive pollutant is called nuclear fallout. Weather patterns determine where and how far the nuclear fallout is carried before it falls back to earth: it could even contaminate environments and resources hundreds of miles away from the original explosion.

Nuclear fallout is most dangerous because it is the most radioactive immediately after the explosion. Thus the land in proximity to the explosion (especially that which is downwind from the point of detonation) is most at risk from the most damage caused by nuclear fallout. If you’re wondering “how far does nuclear fallout travel? because you want to get away from it as fast as you can, be aware that taking shelter is a better choice than trying to outrun the nuclear fallout. The safest place to be is in a bomb shelter!

In order to learn how to build a bomb shelter to protect against nuclear fallout, it is important to better understand this radiation hazard, and to do that, you must learn about nuclear half-lives.

Understanding Nuclear Half-Lives

Nuclear fallout is so dangerous because it is full of radioactive atoms called radionuclides. Radionuclides are unstable and decay over time by releasing energy (radiation) which is harmful to humans. The half-life of a radionuclide is a measurement of how long it takes for half of a radioactive material to decay. Half-lives can be anywhere from a couple of seconds to thousands of years long.

Nuclear fallout usually indicates the radionuclides whose length of half-lives is longer than the duration of the nuclear explosion: those that take longer to decay, and so are still very harmful by the time they finally fall out of the atmosphere, even if its months later.

How far does nuclear fallout travel?

The greatest radiation danger from nuclear explosions come from the radionuclides with very short term half-lives that immediately contaminate the surrounding environment: you have a brief time to get to a bomb shelter before you yourself might be contaminated. Nuclear explosions can cause normally stable material (including organic material) to become radioactive itself. Fortunately, however, the shorter the half-life, the quicker its dangerous effect also subsides.

Another important element that determines the level of radioactive danger is the atomic chemistry of the radioactive element, which determines how easily it can be absorbed into the human body.

Long-Term Global Impact

Now that you understand half-lives and radiation, it’s probably easy to imagine that the global impact of a nuclear explosions is usually caused by nuclear fallout as opposed to the immediate effects of the blast. You can be exposed to radiation either externally (during the blast), or internally by unknowingly absorbing radioactive materials through breathing, drinking, or eating.

The global impact of nuclear fallout

Radioactive material is very dangerous to humans because, once absorbed, they can alter our body’s cells and cause fatal maladies even years later. This is called radiation poisoning, and the effects might not show themselves for a very long long time.

Radiation can cause three types of physical harm to humans:

  • Bodily damage: superficial burns and different types of cancer, including but not limited to leukemia, thyroid cancer, lung cancer, and bone cancer.
  • Genetic problems: birth defects in the children born to parents that had radiation poisoning.
  • Growth issues: the development of intellectual disabilities and handicaps in young infants who received radiation poisoning.

Genetic problems and growth damage are usually caused by very heavy levels of radiation, and so “fortunately” these issues tend to remain contained to the population in closest proximity to the nuclear explosion. Nuclear fallout that is carried far by the wind and eventually contaminates water and food sources (like crops and livestock) elsewhere, however, can still cause long-term effects like cancer.

There are also other long-term effects caused by nuclear fallout that are actually unrelated to radioactivity. For example, all those particles in the air cause a barrier between the earth and the sun: this can alter the temperature on the ground, which could dramatically change harvesting seasons for essential crops, which could in itself disrupt economies across the world and even start famines in poor countries that depend on those harvests.

What to Do During a Nuclear Explosion

Health organizations both on a local, global, and international level recommend standard guidelines to follow in the case of a nuclear blast. Let’s review them before looking into how to build a bomb shelter for yourself.

Before a Nuclear Explosion

As with any cataclysm, the best way to protect yourself and your family is to have a plan before the emergency actually happens. In terms of nuclear explosions, that means knowing how to build a bomb shelter, where the closest shelter locations are outside of your own home, and what to do once you are within them. Ideally, the shelter should be a fifteen-minute walk from your location, because on average, that’s how long it takes for the first wave of nuclear fallout (the most lethal, if you remember from above) to reach the ground in closest proximity to the explosion.

Of course, it’s impossible to have a bomb shelter within a fifteen-minute walk of wherever you are at all times (that would make traveling virtually impossible!) but you can make mental notes of the most viable options for the routes you regularly take. For example, you can think about where you might take shelter along a regular commuting drive either to work or to school. Ideal shelters, besides actual bomb bunkers built precisely for that, are large, sturdy buildings made out of brick or concrete: like schools or apartment buildings.

During a Nuclear Explosion

You might have a warning before an imminent nuclear attack (we have pretty accurate technology for that now) but there is always the slight chance that you either don’t receive the warning, or there simply isn’t any, which means you have to do your best given the situation.

If a nuclear bomb detonates while you’re driving, you should not remain in your car (unless it’s parked in an underground garage), and you should not try to drive away, because it is very difficult to determine what direction the nuclear fallout will be moving in, given the wind patterns.

You should exit your car, head towards the nearest sturdy building, and immediately retreat into its innermost rooms (basements are great), and away from any windows or glass. This will hopefully shield you from early radiation. If you have a handkerchief, cover your nose and mouth to avoid breathing in radioactive particles in the air during any time you spend outside.

Hiding under a bridge to escape nuclear fallout

You might be asking yourself, what if I’m outside, and can’t reach any buildings? In this case, you should seek shelter beneath anything that might protect you from the nuclear fallout. If you are completely exposed with nothing to take cover behind, your best bet is to lie facedown with your hands tucked beneath you, which should protect your exposed skin from burning. Take care not to touch your eyes, nose, and or mouth to avoid spreading any contamination.

Once the initial explosion has passed, you should try and find a bomb shelter as quickly as possible to protect yourself from the first wave of nuclear fallout.

After a Nuclear Explosion

Once you’ve found a bomb shelter, your first instinct might be to leave again to meet up with your family, but you should resist this urge until you’ve heard from emergency response officials. Depending on your location, you might be evacuated, but if local officials don’t request evacuation, experts recommend staying inside. Even just an hour makes a huge difference, because by then, the risk of radiation poisoning could have decreased by over 50 percent (remember that initial fallout is the most lethal, but also has the shortest half-life). You should stay inside at least 24 to 48 hours, and plan on reuniting with your family later.

If the room you are in has air conditioning or heating, you should turn it off, because it is sucking in air from outside without filtering out the radioactive particles, and contaminating the air you breathe.

As soon as you are inside a bomb shelter, you should remove your clothing and wash yourself in order to get rid of any radiation that may have gotten into your clothes or settled into your skin or hair. If there is no available shower, you should take a wet rag and wipe yourself down the best you can, and try to find a change of clothing. You should know that hand sanitizer might be great against Covid, but it does nothing against radioactive material, so go for the good old soap and hot water.

If you are sheltering with your pets, you should apply the same protocol with them: if there is no way to bathe your furry friend, then wipe them down as best as you can.

While sheltering, try any media available to you to stay in contact with local officials, receive guidelines, and communicate with family members. Expect wi-fi to be down, however, and there might even be widespread power outages, as well.

As you might expect, you shouldn’t consume any food or drinks that could have been exposed to radiation: packaged or covered food should be relatively safe.

How to Build a Bomb Shelter

Of course, the ideal situation for a worst-case scenario is that you receive enough advanced warning to retreat into your bomb shelter and wait out the worst of the nuclear fallout. For this to play out, however, you need to know how to make a bomb shelter.

A bomb shelter for shelter from nuclear fallout

A bomb shelter is most effective, in fact, in protecting you from the fallout that follows a nuclear explosion. The truth is that if a nuclear bomb explodes in your neighborhood, even the best bomb shelters are unlikely to protect you from the blast itself, but if you’re far enough away, packed earth does a great job insulating against radioactivity.

Here’s what you should consider when figuring out how to build a bomb shelter:

  • Permission: You’ll need to obtain the proper permits to build an in ground shelter—check with your county before starting your project.
  • Location: Bomb shelters should be located underground, for the reason mentioned above. Don’t dig too far down, however, or you’ll run the risk of getting trapped inside.
  • Consult FEMA (Federal Emergency Management Agency) guidelines for the best saferoom designs.
  • Hire professionals: unless you have professional construction experience, you probably don’t want to do the entire thing yourself. Professionals will use metal sheeting, brick, and concrete.
  • Install living features: including a sleeping area, cooking appliances, and toilet.
  • Stock up: on non-perishable foods, water, a first aid kit, essential medication, a hand-crank radio, flashlight, extra batteries, soap, change of clothes, and anything your pets might need. The supplies should last your entire family at least three days.

Wrapping Up the Question, “How Far Does Nuclear Fallout Travel?”

I hope this post has inspired you to prepare for the unlikely yet not impossible event of a nuclear explosion by learning how to build a bomb shelter. For more nuclear disaster survival tips, check out How to Survive a Nuclear Fallout.