The Effects of a Nuclear Explosion - Study and Preps

The missiles are launched, the reentry vehicles do their job, and mushroom clouds rise over metropolitan America. Could you survive? How? Would it even be worth it?

Recently, I watched a video wherein an individual made certain claims. He was describing the effects a nuclear detonation would have at various distances from ground zero. As I watched, I heard a few points made that didn’t sound right. Now, the effects of a nuclear explosion vary quite a bit from device to device, and even from simulation to simulation, but certain average figures play well with reality. I was trying to determine, from his description, what kind of device was the subject, and whether it was a ground burst or an air burst. One specific claim led me to believe that the weapon in question was of a yield so massive, that we will never see one except in a black and white film.

The Challenge

The challenge I mention in this post was the result of my energetic questioning in the search for “the bomb” that was the focus of the video. I was certain the device did not exist which could produce the effect that caught my attention. As for other claims he made, their verification was dependent upon knowing the source of said claims. It was quite possible that the effects mentioned were either of a heroically large device, a compilation of particulars regarding smaller devices, or even something as simple as rounding errors. I didn’t get very far in my search for an answer. He would not give me the source, only stating that his “research” was beyond my comprehension.  (His reluctance to answer, and instead toss insults my way, were the only related things beyond my comprehension.)  I continued to push for the source, and eventually received one link to basic weapons physics. It had nothing directly to do with his claims, and provided no link to the source. His challenge, however, remained. “Show me I’m wrong”, basically.

Eventually, doing my own digging, I came across this YouTube video.
As I watched, I heard many of the same claims made in the first video (which I will not post as of this time, for reasons of civility, though it is saved on my drive).  In fact, much of the original video’s data and claims appear to be lifted almost entirely, and in great part, word for word,  from the one I located. It appeared that Dr Helfman’s presentation was the sole source for the claims I sought to verify. Taking notes from the gentleman’s video, and reading them as I watched Dr. Helfman’s video, was as if I were reading Dr. Helfman’s own notes.

As such, now having the source information I sought, I will answer the claims that originally caught my attention. But first, let’s establish who the doctor is.

Dr. Ira Helfman specialized in Emergency Medicine, and now practices Internal and Family Medicine. He is associated with Physicians for Social Responsibility, and his PSR Bio can be found HERE. His PSR stated areas of expertise are:

  • Nuclear power nuclear waste, radiation exposure
  • Iran nuclear crisis
  • Nuclear non-proliferation and disarmament
  • Nuclear war, terrorism and preparedness
  • Nuclear Famine

His Bio Sketch says:

“Ira Helfand has worked for many years as an emergency room physician and now practices internal medicine at an urgent care center in Springfield, MA. He is a Past President of Physicians for Social Responsibility and is currently the Co-President of our global federation, the International Physicians for the Prevention of Nuclear War. He is currently working in family medicine after a career in Emergency Room treatment.”

His professional associations include: Co-President, International Physicians for the Prevention of Nuclear War; Chair of the Department of Emergency Medicine and President of the Medical Staff at the Cooley Dickinson Hospital. I could not establish his nuclear physicist credentials, or locate the source of his script.

Another Source?

I did find one more “source”. It is an article that could have been the basis of Dr. Helfman’s script, or have been written based on it afterward. I’m not all that interested in going that far. Maybe it is the origin of the video that started my questioning? Well, it does offer one piece of information that the two videos lack – the bomb size. It is described as a … no, not so fast. I’ll tell you later. First, let’s get into the meat of things.

The Claims

I’ll list here some of the mirrored claims from both videos. The quotes are from the first video (that of my challenger), and are almost word for word from the Doctor’s original (source) video.

“Within 100th of a second, a fire bomb would form two miles in every direction”

“…in this area, the temperature would reach 20M deg, that’s hotter than the surface of the sun (4 mile diameter)
everything would vaporize”

“4 miles out (radius) 600 mph winds; 25 psi, undergrounds shelters would collapse”

6 mi radius – “automobile sheet metal would melt”
10 mi radius – “the blast would generate wind power over 200mph” “10 psi” would level “steel and concrete” buildings
16 mi radius – “anything flammable would burn, like wood, cloth, paper, cloth, gas heating oils”
32 mi radius – “area 800 mi.sq” “1400 deg temps” no O2 “every living thing would die”
greater than 32 mi radius – “crush injuries, blindness from retinal burns”

I’ll mention now that the specific claim that caught my attention, was the 10 psi pressure at the 10 mile radius, or ring. In order to create that kind of pressure, at that distance, a truly huge warhead is required. I wanted to know how big this device was supposed to be, and at what altitude it was detonated. The other data given should support the 10 psi claim, if it were all from the same hypothetical device.

Nuclear Modeling and Blast Mapping

Over the years, the data produced by physical and super-computer testing of specific devices has been recorded and analyzed. Constants and expectations were derived from those studies. The results are charts and formula that make possible, among many things, the creation of broad effect simulators for use on the web. Determining the yield of a device before it is tested can be tricky in that many variables come into play. Nuclear physicists are respected for their mathematical and theoretical prowess for very good reasons. However, once the yield has been determined, either through actual testing of a device, or via a given set of data used as a starting point within a model, the effects can be predicted rather consistently. Consistently enough, in fact, that models for an optimum environment are produced using known data sets, charts and graphs. What this means is, figuring out how powerful the thing is going to be is a problematic endeavor, but mapping its effects are not nearly so.

In general, simulators assume a level terrain with a uniform density of objects upon it, a clear day and some generalization of altitude. Determining pressures from these data only requires a starting point in physical space (whether an actual point or a given region described volumetrically) and an initial pressure at that point or along the spherical border of that region. This pressure is tied to a nuclear device’s theoretical yield.

10 Pounds per Square Inch and 10 Miles from Detonation Point

The question I had was simple. How big of a device does it take to create a pressure of 10 psi at the edge of the 10 mile ring? Which device? The answer was not forthcoming. If you read the preview article, you know that the largest of the weapons built will not likely ever be used because they are obsolete in terms of cost, technology and strategic reality. I knew that whatever the subject device was, it was far to large to be realistically considered for use.

There are a number of test-data-based simulators on the web for general use. They allow a user to model pressure rings based on device yield. Enter in the power of a weapon, or chose from a predefined list, and you are presented with a circular map of pressure regions. Some simulators also produce “effects” such as thermal ignitions, general fallout patterns and supposed deaths. Various simulators have come and gone, and in my experience they are all within a believable margin of error among themselves regarding basic pressure mappings. Most of them assume a ground burst, though a few claim to share results based on optimized altitude for a particular effect from a particular weapon.

Where we might see an anomaly in the pressure maps is in the region of the Mach Stem. The Mach Stem, or Zone, is a circular ring wherein the primary radiating blast wave is caught by the reflected blast wave, and the two values’ additive result is a pressure increase.

Let’s map out the rings, based on the results from a few simulators. They should be very similar to each other and, depending on the engine, perhaps even identical. None should be greatly out of spec with the other. Variations are to be expected and are evidence of good digested data from multiple sources. All of these simulator models can be found on our Nuclear Effects Tools page on this site.

The first simulator run was Nuke Map. Generic settings were initially for a 15MT (megaton) weapon at 11,000′ altitude. The pressure gradients are as follows:

The fireball radius is 1.77mi., or, 9,345 feet. This important for a couple reasons. A fireball at the surface disrupts pressures. A fireball too high will results in pressure drops via expansion before contact with the earth. All distances given in miles.

  • 20psi = 3.9
  • 10psi = 5.91
  • 5psi =9.03

With these settings, we can see that the magical 10psi at 10mi has not been achieved. Playing with altitudes give us these results:

Same fireball radius. After all, it’s the same device…


  • 20psi = 3.52
  • 10psi = 5.22
  • 5psi = 7.97


  • 20psi = 4.3
  • 10psi = 6.53
  • 5psi = 9.69

As the altitude increased, the pressures did as well. But at some point, it should fall off.

  • 20,000′
  • 20psi = 2.79
  • 10psi = 6.67

At 23,000′, the 10psi ring dropped to 5.96 miles. The device used here is similar to the one yielding 15Mt at the BravoBravoC640c10Castle Bravo shot. It was a runaway bomb expected to give us somewhere in the neighborhood of 7Mt, but generated a runaway reaction due to a Lithium 7 “miscalculation”, or rather, the Lith 7 poisoning. We have never popped a nuke bigger than that. But we’re aren’t going to bomb ourselves, are we? What shall we expect the Russians to use that could possibly generate 10psi at 10 miles? Let’s up the yield and see.


A 25MT bomb, optimized for 10psi does so at 8.06 miles. Taking it to 50MT, and we get our magic 10.02 mile pressure ring, from a 27,000′ altitude.

So, according to NukeMap, we need an airburst weapon yielding 50Mt to create 10psi at 10 miles. Discounting for now, that such a device is not in the strategic inventory of the former USSR or modern day Russia, let’s look at the other data generated for this scenario, as relates to the claims the good Doctor made.

Our Big Bomb produces these effects:

  • Fireball radius = 2.87
  • 20psi = 4.21
  • 10psi – 10.02
  • 5psi = 15.2 (Severe destruction to stick-built homes.)
  • 1.5psi = 34.4 (Window breaking range.)
  • 3rd degree burns = 37 (Guaranteed 3rd degree burns for exposed flesh, unshielded.)
  • Thermal burn-free = 79.9 (At approximately 80 miles, there is no burn effect.)

Some of these appear to be in keeping with the 50Mt simulation, so we won’t go much further with those. Back to the bomb….

The only test of a weapon this large was the October 30, 1961 test of the Soviet AN602 -Tsar Bomba. It was a 100Mt weapon (claimed), “detuned” to 50Mt. It’s burst height was less than half of our model’s test, at just under 13,100′. Interesting, huh? (Our model places the 10psi ring at 8.36 miles for that altitude).

How likely are we to see a 50Mt device used in actual nuclear warfare? Let’s look at the Soviet, excuse me, Russian, stockpiles.

According to the Center for Strategic & International Studies, Russia has 960 warheads that are “on alert” with somewhere above 2,000 classed as “nonstrategic” and in some form of readiness.  Nuclear Files states that the Russians have 2,050 nonstrategic warheads, and 2,790 strategic warheads.  It’s those 2,790 that we need to look at. Just what are they, and how might they be delivered?

The Estimated Strategic Weapons Inventories (2004) lists inventories and yields as 2004. Federation of American Scientists, (FAS) also list Russian weapons as recently as 2009, and between the two sources, we can report on weapon types and yields with some degree of certainty.

Russian Nuclear Weaponry – Deployed Types

According to FAS, the majority of 4 – 10 MIRV land launched missiles in Russian inventory have been either decommissioned or reduced to 4 or 1 warheads. The larger devices have been culled, with the last of them seemingly discontinued around 2009. If a few remain, they are most certainly targeted against NORAD, or our super-hardened silos. City killing, it appears, is left to the “smaller” devices. The latest dated reference for the FAS report linked to from here is from 2013.

ICBM (Inter-Continental Ballistic Missile)

SS-18 Status

  • SS-18 M5 550 – 750kt
  • SS-18 M6 20Mt. — (Decommisioned 2009)
  • From Wiki, With the retirement of the 20 megaton SS-18 Mod 6 warheads, the highest yield weapon in service with any nation is the estimated 5 Mt (China)

SS-19 Status

  • SS-19 – M1 500 – 750kt
  • SS-19 – M2 5Mt (Decommisioned in favor of the Mod3)
  • SS-19 – M3 550 – 750kt

SS-24 Status24 550kt (Decommissioned April 2008)

SS-25 Status Topol2 – Road Mobile – 550 – 800kt

SS-27 Status Road Mobile, RV capable of evasive maneuvers – 800kt

SLBM (Submarine Launched Ballistic Missile)

SS-N-18 Status : 100kt – 450kt, maximum 4 MIRVs per missile

SS-N-20 Status :  100kt, 10 MIRVs per missile

SS-N-23 Status : 100kt, 4 MIRVS per missile

ALCM (Air Launched Cruise Missile)

Bombers ALCM  Mostly 100 – 200kt weapons.

It is the land based missiles that carry the heavy loads, and the last of the large payloads appear to have been pulled from service.

So, what was that “one more source” I referred to earlier? It is an article by Alan Peters. His bio reads:

“For many years involved with intelligence and security matters in Iran with significant access at top levels during the rule of the Shah, until early 1979. Currently an Iran SME (subject matter expert), analyst/commentator, and multi-linguist.”

An intelligence analyst from 35 years ago, linguist and SME. I don’t know if he is current. The bomb, he claims, that will do all this mahem is – drum roll please – 20Mt. That’s all. Just 20Mt. I find it heartening to know that the Sov, er, Russian inventory is made up of significantly smaller weapons, don’t you? No Tsar Bombas to haunt us – except in an old black and white film.

My challenger asked if I know any nuclear physicists, and stated his information came from the world’s top physicists. Dr Helfman, and Mr. Peters certainly have experience, but are they physicists?

So, Can You Survive?

USS1Sharon Packer, of Utah Shelter Systems is a qualified expert on the topic of nuclear warfare preparations. She has a degree in mathematics and a minor in physics at the University of Utah. She later earned her masters in nuclear engineering. Sharon states, “The ultimate purpose to my degree, however, was for the design and construction of nuclear shelters.” Her thesis was included in a 150 manual titled “Nuclear Defense Issues.” Working with Ed York, a nuclear engineer for weapons testing at the Nevada test site, she has acquired the expertise to evaluate nuclear weapons effects, and design some of the best blast /fallout shelters in the world. Other companies have shamelessly copied the USS designs….

From the Utah Shelter Systems website:

“People housed in hardened blast and radiation shelters, such as are built by Utah Shelter Systems, would be expected to survive all NBC weapons effects at ground zero from an air burst (50 psi), and at one quarter mile from the crater edge from a one megaton yield ground burst. At that proximity, an 8 ft. diameter shelter must have at least 8 feet of dirt cover. A 10 foot diameter shelter must have at least 10 feet of dirt cover over head. Each person must have approximately 10 square feet of shelter space for short term survival (up to 2 weeks). Double this space requirement if the shelter is to be used as a permanent residence.”

I asked her about this claim on one occasion. How can a nuke blast, over your head, not kill you and everything in the shelter? Her answer was that the “earth arching” involved in shelter installation provides for 250 psi overpressure. Earth Arching is a novel the reality of earth borne pressure equalization of a buried cylinder. Take for instance, a 10′ diameter culvert shelter. If installed properly, which means burying it such that there is a thickness of earth covering it equal to its diameter, the curve of the hull forces the earth to arch. 10 feet of earth above the hull works against the surrounding earth much like flying buttresses held aloft the huge and precarious ceiling of the old European cathedrals. Most of the force applied to the top of the shelter is directed away from the hull and into the earth. Flat roofed shelters absolutely can not claim this.

Since most Russian airburst weapons are below the 250 psi range at ground level, and its not likely that one will land on you, given time to get inside, a family can survive. From that point, continued survival depends on the prepper’s planning: food and water stocks, medicine, radiation meters, communications and defense.

I did several studies on the effects a a 1.5Mt weapon blowing at a strategic point 14 miles from me. My place will suffer broken windows and maybe some damaged roofing. I drilled that thing over and over. We might get something bigger, but I doubt it. Might even get two or three there, but the cumulative effects, while not nice, don’t spell disaster.

My challenger stated he has a cabin, on the back side of mountains at 14,000 feet, 50 miles away. He should be fine if he can get there, or even be on the other side of the mountains if one goes off. He is 15 miles or so from NORAD. If he is home at that point, I think it will be a rough ride. Give the man a shelter, though, and he’ll do well, as long as he hardens his intakes, and prepares at least one of the entrances with a debris proof shield.

HikingThroughMeadowAmericans living outside the cities should still prepare, in the face of such doom and gloom as presented in so many videos and studies. I feel those things are irresponsible. They suck the hope from those that DO have a chance, and shove them into a defeatist mentality. As preppers, we are to honestly evaluate things, and do “what we can” to create an internal strength equal to the times. Some things are just not survivable, and it truly makes little sense to worry much about them – even though some still require planning. Example? The man who knows he is going to die of a heart attack, or cancer, should have his estate in order for his survivors, to limit their expenses and maximize their inheritance. Everyday things like that are important, too. But the big things can be just as easily planned out. In the case of nuclear war, those who survive the first hour can survive much much longer if they have plans and preps in place to deal with it.

And there will be many that survive the exchanges, and drift about through the wreckage of cities. Do you want to live among them as they claw about? Or would you rather live past that point and join those ready to rebuild?


Reference Sites

Federation of American Scientists
FAS – History of the Russian Nuclear Program 2013

Tsar Bomba Sources

The original, November 1961 A.E.C. estimate of the yield was 55–60 Mt, but since 1991 all Russian
sources have stated its yield as 50 Mt. Khrushchev warned in a filmed speech to the Supreme Soviet of the existence of a 100 Mt bomb (technically the design was capable of this yield). Although simplistic fireball calculations predicted the fireball would hit the ground, the bomb’s own shock wave reflected back and prevented this.[9] The fireball reached nearly as high as the altitude of the release plane and was visible at almost 1,000 kilometres (620 mi) away from where it ascended. The subsequent mushroom cloud was about 64 kilometres (40 mi) high (over seven times the height of Mount Everest), which meant that the cloud was above the stratosphere and well inside the mesosphere when it peaked. The cap of the mushroom cloud had a peak width of 95 kilometres (59 mi). The base of the cloud was 40 kilometres (25 mi) wide. All buildings in the village of Severny (both wooden and brick), located 55 kilometres (34 mi) from ground zero within the Sukhoy Nos test range, were destroyed. In districts hundreds of kilometers from ground zero wooden houses were destroyed, stone ones lost their roofs, windows and doors; and radio communications were interrupted for almost one hour. One participant in the test saw a bright flash through dark goggles and felt the effects of a thermal pulse even at a distance of 270 kilometres (170 mi). The heat from the explosion could have caused third-degree burns 100 km (62 mi) away from ground zero. A shock wave was observed in the air at Dikson settlement 700 kilometres (430 mi) away; windowpanes were partially broken to distances of 900 kilometres (560 mi).[10] Atmospheric focusing caused blast damage at even greater distances, breaking windows in Norway and Finland. The seismic shock created by the detonation was measurable even on its third passage around the Earth.[11] Its seismic body wave magnitude was about 5 to 5.25.[9] The energy yield was around 8.1 on the Richter scale but, since the bomb was detonated in air rather than underground, most of the energy was not converted to seismic waves. The TNT equivalent of the 50 Mt test could be represented by a cube of TNT 312 metres (1023 feet) on a side, approximately the height of the Eiffel Tower.

The Tsar Bomba is the single most physically powerful device ever used by mankind.[12] By contrast, the largest weapon ever produced by the United States, the now-decommissioned B41, had a predicted maximum yield of 25 Mt, and the largest nuclear device ever tested by the United States (Castle Bravo) yielded 15 Mt (this was due to an unexpected runaway lithium-7 reaction; the preliminary prediction for the yield was from 4 to 6 MT: a 6 Mt maximum predicted yield). The largest weapons deployed by the Soviet Union were also around 25 Mt, as in the SS-18 Mod. 3 ICBM warheads.

Nuclear Weapons Archive
Effects, Chp5.4.1 Air and Ground Bursts
Russian Nuclear Weapons Lists – Historical
DoD Report, 2010, showing that the DoD believes the chances of survival are great enough to warrant planning.


Simulators and Tools from our Nuke Effects Page
Here are some tools to evaluate your own situation. With these, you will be able to check your findings from one against another, and cross to official documents.

Nuke Map – A simulator that allows for Airburst altitude settings. It has an Advanced Options tab that allows for a great deal of customization. Alex Wellerstein is the creator.

Alex Wellerstein, American Institute of Physics.
“(Despite the position title, I’m an historian, and have never been a physicist.)”

Excellent resource for searching articles of the nuclear type. ALSOS – Digital Library for Nuclear Issues

High Yield Detonation Effects Simulator – (HYDESim)
Enter an address to move the point of impact to “ground zero”. 1000KT = 1MT.
The data used in HYDESim are based on information found in “The Effects of Nuclear Weapons”, 3rd Edition, by Samuel Glasstone and Philip J. Dolan.

Nuclear Weapons Effects Calculator – Federation of American Scientists (FAS) – Provides fro ground or air bursts.
“This interactive tool is intended to give an idea of the devastating blast effects of ground-level, shallow subsurface, and low-altitude nuclear weapon detonations. It is relevant to traditional nuclear weapons, potential terrorist attacks, and next generation nuclear weapons such as “Bunker Busters” or “Robust Nuclear Earth Penetrators” (RNEPs).”

Ground Zero II – from Carlos Labs
“Have you ever wondered what would happen if a nuclear bomb goes off in your city? With Google’s Maps framework and a bit of Javascript, you can see the outcome.”

Missile Range Map Tool – from Carlos Labs
“In the last few years, missiles and launch systems have become the new bargaining chip in international diplomacy.”

Create a Nuclear Firestorm – Nuclear Weapons Explosion Simulator
A rather comprehensive data generator.
“The data and algorithms used to create these simulations are based on information found in “The Effects of Nuclear Weapons”, 3rd Edition, by Samuel Glasstone and Philip J. Dolan. Thanks to Dr. Alexander Montgomery and Dr. Lynn Eden for their assistance.”

“Choose a city or location (type in an address) and select the size or type of nuclear weapon to be detonated. Depending on the weather conditions, the size of the certain and probable area of the nuclear firestorm, created by the nuclear explosion, will vary.

The model used to approximate the size of the firestorm is accurate in the range of 10 to 20%. The simulator can produce this degree of accuracy for explosions that range from 15 kilotons to 2000 kilotons (2 Megatons or 2 MT).”

Nuclear Bomb Effects Computer
Go to the bottom of the page for the web-version. But for interesting reading, read about the “slide rule” calculator the simulation is based upon.

FAS – Fallout Calculator
“This java-based interactive calculator shows the distribution of fallout, by wind, from nuclear bomb blasts of various yields. The contours depict calculated radiation doses of 300, 25, and 1 REM at 96 hours after detonation.”

Impact of Low Yield Nuclear Weapons – “Suitcase” Nukes, and Their Effects
Data and summary of the effects of 1, 10 and 25KT weapons.


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