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How to survive a nuclear bomb: An update on "Duck and Cover"


March 12, 2014

US Atomic Energy Commission 14 kT Bunker Charlie test - October 30, 1951 (Photo: USAEC)

US Atomic Energy Commission 14 kT Bunker Charlie test - October 30, 1951 (Photo: USAEC)

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The best advice for surviving a nuclear bomb is to be somewhere else when it goes off. If that doesn't work out for you, though, a recent study carried out at the US Department of Energy's (DOE's) Lawrence Livermore National Laboratory (LLNL) provides some simple guidance for maximizing your chances of survival.

In a world where terrorists or small states may be able to muster a 1-10 kiloton nuclear attack, a prudent individual might find it worthwhile to decide a course of action ahead of time. LLNL's Michael Dillon had been studying nuclear shelters for many years when his family asked what they should do if they see a nuclear mushroom rising over their city. Not having a good answer, he began putting together survival models. It turns out that the decades-long advice to shelter in place is not necessarily the best plan for survival.

The first step in surviving is making it through the initial detonation. A credible threat is a 5 kiloton pure fission explosion that detonates in a building at a height of 60 m (200 ft). The energy of the explosion is distributed between blast (about 50 percent), thermal radiation (about 35 percent) and ionizing radiation (about 5 percent in the initial burst, and about 10 percent in fallout.)

Using NUKEMAP to model the effects of the explosion, the figure above shows the effects of the blast if located in the Empire State Building in Midtown Manhattan. The inner black circle is the size of the crater, and the red ring marks the edge of the 20 psi overpressure zone, wherein most buildings will be destroyed. The green ring marks the zone where an unprotected person will receive a marginally lethal dose of prompt radiation, and the peach ring, which has a radius of 1 mile (0.62 km), is the region in which second-degree thermal burns are likely. Outside of this region an unprotected person has a decent chance of surviving the prompt effects of the blast, if they don't get hit by debris (Duck and Cover!)

The expected death toll from prompt effects, such as blast, heat, and the initial burst of radiation, depends on the city and location within the city. Prompt effects from the New York city blast shown above would kill nearly a quarter million people, while if the same blast were centered on downtown Albuquerque (a spread-out small city with a well-defined downtown) the prompt death toll would be about 15,000.

Assuming one has survived these early effects (although you may not be sure about survival until a couple of weeks have passed), the next object is to avoid being killed by radiation exposure from the fallout. Exposure to radiation is measured in a variety of units; here we will use rems (Roentgen equivalent man) and rems/hr. The lethal dose is about 500 rems. (Another commonly used unit for radiation exposure is the Gray (Gy), which is equal to 100 rem.)

The fireball is 760 ft (230 m) in diameter, large enough to touch the ground, producing substantial local fallout. The mushroom cloud climbs for a period of about five minutes, reaching an altitude of about 3 miles (4.8 km) and a diameter of about 2 miles (3.2 km). The total amount of radioactive material resulting from a 5 kt explosion is only about 1 lb (0.5 kg), but that material is extremely radioactive.

Fortunately, the fallout is not evenly spread. The most intense radiation products for this size of blast remain within the prompt kill zone of the bomb. Assuming a wind speed of 10 mph (16 km/h), the fallout is distributed over a narrow plume, as shown in the figure above. The area in which the radiation exposure rate is between 100 and 200 rem/h reaches about 4 mi (5.4 km) downwind of the detonation, but is only 0.33 mi (0.54 km) wide. For a rate of 10-100 rem/hr, the region is 15 mi (24 km) long and 1.5 mi (2.4 km) wide, and for a rate of 1-10 rem/hr, it is 26 mi (42 km) long and 2.8 mi (4.5 km) wide.

Should I stay or should I go?

Now comes the question: What will you do? The official US government guidance is to shelter in place. You go to the nearest and most protective building and stay there for 24 hours unless told to evacuate sooner.

This isn't bad advice if your immediate shelter is the basement of a more or less intact house, which can reduce radiation levels by a factor of ten or so. However, if the blast occurs in Los Angeles rather than in New York, the lack of a frost line allows most houses to be built without basements. Such houses only block about half the fallout radiation.

Taking into account the decay rate of the fallout, a location with an initial exposure rate of 200 rem/h (about the highest dose rate for fallout from a 5 kt device) will receive a total radiation exposure of over 600 rem in the first 24 hours. If sheltering in a NYC concrete basement, a person's exposure in this period would be about 60 rem, an exposure having little immediate health consequence. However, in an LA ranch house, over 300 rem would be absorbed in that same 24 hour period, which would prove an eventually lethal dose for a substantial number of victims receiving little or no medical care, particularly if combined with flash burns and blast debris injuries. It would appear that sheltering in place is not necessarily the best advice, depending on local circumstances.

Another factor to consider is, if the wind direction is constant, it shouldn't take long to leave the worst of the fallout plume by walking perpendicular to the plume. It also requires time for radioactive materials to fall to the ground, even near the blast site. This can provide a short period during which radiation exposure is not the greatest concern. Instead, dodging falling buildings, debris, and fires is likely the biggest risk in this early post-blast environment. Still, there is time and opportunity to take a different course than simply sheltering in place.

It is this opportunity that Mike Dillon decided to analyze. He developed a complex mathematical model describing the radiation exposures associated with different post-blast behaviors, then simplified the results so they can be used by anyone to choose a survival strategy.

The key factor is how long it would take to get to an adequate shelter. For a 5 kt blast, adequate shelter is essentially either a standing multi-story building (shelter is best in the mid-upper floors), near the center of a large concrete or brick building, or in a structurally sound basement.

If it would take you less than five minutes to reach adequate shelter, go there immediately following the immediate blast effects. In the end, the better shelter will offset your brief exposure to higher levels of radiation.

If adequate shelter is less than 15 minutes away, shelter in place for no more than 30 minutes, then transfer to the better shelter. Again, the combination of a short period of immediate shelter combined with a move to better shelter will offset your exposure during the move (at least statistically).

The choice of a 5 kt nuclear device was intended as something that could be made by terrorists or small states with a minimum of sophisticated design. As a result, if positioned more than a mile from the detonation, a person has a pretty good chance of surviving the attack. Even the area over which large areas of fallout land are quite small, with the 100 rem/h contour taking in about 1.5 sq mi (3.8 sq km).

The story would be quite different if a Minuteman or Trident-class weapon were stolen, as these have yields in the general vicinity of 300 kt. Such a device would have a prompt kill range of about 5 miles (8 km), causing the deaths of about a million people in the Empire State Building scenario. The 500 rem/h fallout contour includes some 50 sq mi (130 sq km), and the 100 rem/h region covers some 400 sq mi (1,036 sq km). Despite the enormous size differences, Dillon's rules still can help. It is just that many more people would die of fallout regardless of their course of action.

Should a nuke ever be detonated in a city anywhere in the world, the results would obviously be enormous, but of similar dimensions to the largest weather-related disasters and earthquakes. We would survive, but it would be a blow never to be forgotten. Let's hope we never go there.

Source: Proceedings of the Royal Society

About the Author
Brian Dodson From an early age Brian wanted to become a scientist. He did, earning a Ph.D. in physics and embarking on an R&D career which has recently broken the 40th anniversary. What he didn't expect was that along the way he would become a patent agent, a rocket scientist, a gourmet cook, a biotech entrepreneur, an opera tenor and a science writer. All articles by Brian Dodson


there are currently no deployable nuclear weapons with anything like a 20MT yield.

Most submarine-launched ICBMs have between 20kt and 300kt potential, while the most powerful land-based ICBMs are 1MT, though most are less.

China has a handful of long-range ICBMs with estimate yields of 4-5MT, but they only have 20 or so of these.


The premise of this article is a 5 kt (kiloton) explosion at ground zero. That's utterly unrealistically small! Modern weapons are in the mt (megaton) range with a typical warhead around 20 mt.

Now think about how far the destruction and contamination would spread from a 20 mt (or more) blast...


'but of similar dimensions to the largest weather-related disasters and earthquakes'

Unfortunately the overall impact of a nuclear detonation will be a lot worse due to the long and medium term impact of the exposure to radiation, including cancers and birth defects. The fallout area will be unusable for a long period of time. Natural disaster are more time limited, with immediate deaths, injuries and with fewer long term consequences.

Brian M

Perhaps the biggest threat these devices pose is not the actual number of casualties that would result from their detonation, it is the threat they are capable of posing.

Give any terrorist organisation a few of these, such as might happen if someone breaks the padlock on the garden shed in which are stored a number of battlefield nuclear weapons, and they could have any nation belly up within a few short weeks. All that they would need to do is simply detonate them randomly one at a time without warning in various centres of population. A few days between some, a week or so between others with perhaps even a month on one occasion, just to give some false hope to the populace that the nightmare was over.

How long then before those living in any population centre fled to the hills? How long then before the food ran out? How long then before the population became feral, scavenging for food, searching for uncontaminated water, etc.? Imagine such a scenario in a nation personally armed to the teeth. The military would have no identifiable target to aim at, and anyway, it would soon be severely diminished due to troops deserting in order to defend their kith and kin. The struggle to return to what might be called civilisation would take many years, during which time any position in world governance would be long gone, probably never to return.

One has always to try and spot the politics in such press release items as this one. Do the authorities know something we don't? My personal test as to whether terrorists have managed to obtain nuclear weapons is if, when I turn on the radio first thing on the first of January, the programme is not discussing the destruction of New York at the instant the Time Square countdown to the new year reached zero. This is closely matched by the lack of the destruction of Washington during the State of the Union address to both houses. The first would be symbolic, New York being the home of capitalism; the latter much more effective by removing the governance, leaving the chicken headless, so to speak.

Any talk of a nation's ability to launch nuclear tipped missiles is a diversion. It would be folly to do so, seeing as the point of origin would be known. In contrast, you cannot put the pieces of an atom bomb back together in order to obtain clues as to its manufacture. The scary thing is that there could already be in situ such devices, their electronic timers counting inexorably towards a fate that none of us would wish on our worst enemy.

Mel Tisdale

If you see a large flash, hit the ground and cover your ears tight to absorb some of the concussion a second later.

Radiation enters mostly through the respiratory tract and open wounds. As such, the following would be handy to stash at home or work in some kind of solid box: 1. iodine tablets 2. better then p100 class particulate respirator with spare filters to last at least a few days (each filter good for ~4-8 hrs continuous operation depending on fitness level and exertion). 2. painter's disposable suit 3-4 of to change daily 3. first aid kit. 4. 10L of water bottles in a backpack.

If you survive the blast, find these items, pop the pills, patch and wash your wounds immediately then put on the suit and mask.

These things together costing less then $200 will put you further ahead of the curve.


The article forgets to mention the subway. It is probably the best shelter in downtown NY and its tunnels allow you to move out of the danger zone while being pretty well protected from the fallout. So if you have a subway in your city, you are lucky... The article also forgets to mention that concrete buildings are a very good way to block the blast and the heat. The more tall buildings made from concrete and steel a city has, the smaller the radius of destruction. Because of this, the higher yield bombs are generally exploded higher above ground. This also means that simply putting a 300kt bomb on top of the empire state building will not automatically result in that much more damage compared to the lower yield bomb (and the effect generally does not scale linearly). I also want to point out to Brian that birth defects and long term cancer is generally exaggerated by popular media. I suggest to read up on the so called "life span study" about the survivors of Hiroshima and Nagasaki. If you survive the initial blast (without severe injuries or maximum exposure) and get treatment right away, your life span will be minimally reduced. Birth defects as a result of the radiation are rare. Another good advice that was not mentioned here is to protect your mouth with a makeshift filter of sorts to avoid inhalation of radioactive particles. External exposure to radiation is a lot less damaging than internal exposure. So avoid ingesting or inhaling radioactive particles and try protecting your eyes with glasses. A full face gasmask would probably be ideal, but most people don't have access to that.


Mel, get a grip. This article is based on a paper submitted to the Royal Society last October. If the government has new information about a threat, it is not imminent.

Do the authorities know something you don't? Yes. They know nuclear weapons are not stored in garden sheds. And they do know how to analyze a nuclear explosion to trace the fissile material back to the source. If it was a stolen weapon, it would still not mean they would know who set it off, but if it were terrorists, they usually take credit. So the response would probably not be a nuclear missile, but more likely an air strike or a Seal team.

Read Cresson Kearny's 'Nuclear War Survival Skills', stockpile food and ammo and some old Jerry Ahern 'Survivalist' paperbacks in your bunker and try not to worry.



Whilst nuclear weapons are not stored in garden sheds any longer, when the Cold War came to an end it was discovered that the storage of Soviet battlefield nuclear weapons was as good as their being stored in sheds with padlocks under the guard of a disillusioned soldiers who were unpaid for many weeks at a time. How much do you think a battlefield nuclear weapon would have fetched on the black market?

Regarding your point that terrorists "usually take credit", "usually" is no guarantee that they always will, and anyhow, going back to the days that the U.K. was under threat from the IRA, where exactly would we have pointed our 'deterrent'? Belfast maybe? Dublin possibly? I think you will find that it isn't me who needs to get a grip. We have missed a glorious opportunity to make the world a safer place following the end of the Cold War thanks to complacency. Now where are we? Not in the place we should be in if we didn't have such a bunch of clowns for politicians, that's were.

Mel Tisdale

I recommend what the government had us do in grade school air raid drills in the early 50's. Crouch under your desk and kiss your little ass goodbye.

Bob Higgins

Really? I have just a couple of question... what are you going to breath, how long do you expect you food stuffs to last? Not to mention how will you protect yourself from those who want what you have and will eventually get it. Also even if you do survive, then what and so what? How pleasant do you think it would be being the only few left on a planet or continent to start civilization all over? No thanks... I would rather be at ground zero so as not to have to waste my time with all these fluffy thought of a great outcome. Because you're going to die one way or the other and if you would rather be in a confined space watching your limited supply of everything deminish as the inevitable comes about more power too you.


The suggestion for retreat is made interesting as in, trapped in your car, stuck in a traffic jam... When a hurricane approached Houston, it was a spectacular nightmare of epic proportions of fleeing Houstonians.

If the area is not on fire, and many areas will be burning, bunkering down in the center of your house is an option. Plug up doorways, pull heavy objects, even books near this center retreat area... and take that Iodine! Make shift masks out of wet cloth can help. And take at least some time to bring in with you as many gallons of water as you can as the lack of water will kill you faster than many can think. As fat Americans we carry our food, water, not so. Later you can think of retreating past all of the dead and dying stuck on the road. Sound like movie material...


I have a book in my library called "Forecast 2000", by joseph pulitzer jr. published in 1984. It mentions a possible attack from "terrorists" in the form of a threat of detonation of a nuclear device from the Empire State Building...how prescient.

On the other hand, what advice could we have given to the residents of Hiroshima, Nagasaki or Faludjah, Iraq?

This is a complicated and risky new world we're living in. There are many things done by state governments that can be counter-productive in the name of security. So we go on living in spite of it all, because having a dreadful existence is no way to live...

Just make sure your pantry is full and you have at least a rudimentary supply of necessities.


This is crazy! Get a grip on reality people.

We need to start thinking outside the military industrial complex box that even gives a voice to this Armageddon scenario. We don't have to be forced into these false choices of "security". What is lacking is understanding that tensions can be diffused without the use of weapons.


Perhaps Jiddu Krishnamurti said it best: "It is no measure of health to be well adjusted to a profoundly sick society."

And Einstein, who contributed greatly to this mindset, also offers sage advice - "We cannot solve our problems with the same thinking we used when we created them."

I'd like to see some out of the box suggestions on eliminating inequality in the world-the root cause for our military and its evil inspired endeavor.


"The green ring marks the zone where an unprotected person will receive a marginally lethal dose of prompt radiation … ". Marginally lethal? Does that mean you're vaporized, crisped, medium rare or what?


On a somewhat related note. Depleted Uranium from weapon munitions is arguably the worst WMD life can encounter. Don't be fooled by its innocuous sounding name.

The resulting radioactive fine dust (and you think fine dust from cars is already bad) can be carried virtually everywhere by wind. When it is inhaled it causes terrifying birth defects and cancer-related diseases. This happens regionally on a short time span where it was used, but given its stupendously long lifetime (billions of years), it will keep wreaking havoc to life everywhere it is spread overtime. Hundreds of tons was used in the Gulf and Iraq. They will not be the only ones to suffer.


The decision to use indiscriminate weapons comes very normally for the Pentagon since its founding, albeit always in a new way. Carpet bombing of Germany, nuking Hiroshima and Nagasaki, Agent Orange in Vietnam, white phosphorus and depleted Uranium. The Pentagon is a very efficient operating bureaucracy, where no opinion of a single person has much impact on decisions. That is why "it" lacks a human character and can whip up measures that fulfill military objectives with the least strategic losses, but often with horrible human and ecological cost.

Fretting Freddy the Ferret pressing the Fret

I hope this topic is a peculiarly American fascination. It's weird.

T N Args

It's OK as long as you can say "WHAT WAS THAT?"


If a terrorist lets off a nuke in some western city, it would be a test of that government's nerve and maturity to not overeact. Like 9/11 the images in particular would be so powerful, unlike anything we've seen, that it would be hard not to respond with war. But tipping the world into such chaos while seeking a futile revenge would cause much more suffering and destruction than even a nuke can deliver.


Who else has ACTUALLY deployed atomic bombs and depleted uranium weapons other than the US?


I gather all those REM exposure numbers were "calculated" long ago by victims of blasts (in part, in the pursuit of compensation). When those numbers were later applied to other disasters, they totally failed to predict the observed outcomes.

Bottom line - I think there's no accurate measure around of the actual danger of radiation, and from disaster observations, it's absolutely nowhere near as bad as people have been believing all these years.

And, FWIW, remember that fear is way more powerful than those bombs anyhow...


When I was in grade school, "duck and cover" meant, "Bend over. Put your head between you knees. Grasp your ankles tightly, And, kiss your ass goodbye."

Humans seem incapable of learning from anything.

Jakob Stagg

Actually the nuclear bomb is the least of our worries. It's the public's reaction to it. In the 1950s my grandparents and many others had a small farm, a couple milk cows, a chicken house, a large garden, a cellar full of canned goods, and a gravity furnace that would operate on coal or wood. If the stores were empty, electricity failed, or no gas; it would have been a minor inconvenience. They were pretty much self sufficient. Now jump forward 60 years and see what modern civilization has done for us. Almost nobody knows how to grow or can their own food, the grocery stores are only three days from empty, Without gas or electricity our appliances don't work and our homes are cold. We have basically become too civilized to survive. Back in the "duck and cover" days of the 1950s, a nuclear attack would have been much more survivable. Today any breakdown of our "just in time" supply systems would create tremendous riots and panic while a counter-strike on a third world terrorist country would have minimal effect since they still get along pretty much like our grandparents did. Until a large portion of our defense budget is invested in rotating stockpiles of water, food and energy distributed all over the country, we are sitting ducks for a terrorist attack. Homeland security as it now stands is just a cruel political joke. With our current system the lucky ones will die first.


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Barry Cohen

Pucker up Buttercup and kiss your heiney goodbye !

No amount of prepping can prepare you for a nuclear war, even a limited engagement of two or three detonations. Any detonation of the nuclear variety would produce an and EMP that would knock out the power grid---uh forever. Then said affected area would be contaminated for years along with any ground water, plants,trees and animals. MAD=Mutally Assured Destruction.

I personally think society would collapse in 15 minutes because people wouldn't be able to check Facebook, or use their cell phones.

Nukes were great weapons......when our all of enemies didn't have them.

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