The Destructive Effects of a Nuclear Suitcase Bomb

The dust is settling on the conflict in Afghanistan and not one major figure from the Taliban or Al-Qaida has been found. Bin Laden remains elusive and, according to some reports, he may have moved to the Pashtun-dominated area of Pakistan weeks ago.

In that sense, Operation Enduring Freedom is so far a failure. And that leaves one vital question still open. Does Bin Laden still own the fabled nuclear suitcase bomb?

We can safely assume that nothing of that nature was found in the Tora Bora complex. One does not abandon equipment that cost millions of dollars, especially if a heavy American attack on Afghanistan was worked into Bin Laden's war game tactics prior to September 11th.

The answer, in my opinion, is somewhere between probably and not likely. But, whatever one's view is, the major question is concerned with what these devices are capable of. The answer to that depends on a number of different factors which I shall explore below. A likely scenario of bomb parameters will be used and we shall arrive at a set of numbers, which will show only too clearly what an undesirable visitor such a device would be to an American city.


The first parameter to establish is the explosive yield of the device. Based on the various media reports and articles I have examined, the alleged nuclear "backpacks" or "suitcases" would appear to be in the one to ten kiloton range. As a benchmark, the uranium fission bomb dropped on Hiroshima was just over ten kilotons. However, the majority of the articles tend towards the lowest figure of one kiloton and that is the number I will assume.


The mode of detonation is very influential as to the range of the effects of the nuclear explosion and is partly dependent on the intentions of the terrorists. High altitude airbursts are normally intended for Electromagnetic Pulse (EMP) effects — i.e. to knock out electronic command and control equipment. But this is not useful to terrorists and is useless anyway for such a low-yield device.

A ground burst minimises blast and thermal damage due to the shielding of successive buildings and hills but maximises the production of fallout particles. These particles are vacuumed up into the initial fireball, which vaporises and then irradiates them before they condense back into solids and float down to earth within hours.

Finally, a low altitude airburst would balance blast, heat, and fallout damage into one infernal combination and has the dubious but added "bonus" of the Mach Effect, which is a reinforced blast wave, created when a fireball blast wave meets the initial blast wave reflected from the ground in the manner of constructive interference.

Which method would a terrorist choose? I suggest the low altitude airburst since it is emotive pictures of decimated sectors of cities and high numbers of immediate casualties that they want the world to witness. For sure, fallout from a ground burst could kill many more over the following months and years, but that does not generate the razor-sharp publicity that a terrorist hungers for.

But could a terrorist pull off a low altitude airburst? The only conceivable way to do this is to carry the weapon over ground zero in a light aircraft. Getting the aircraft would probably be quite easy as would be the loading of the device. Flying the aircraft over the city is more difficult, but once again the nefarious deed could be executed before the military were alerted, scrambled a fighter jet, and engaged the enemy. The likelihood of a USAF fighter catching such a plane is also diminished if a lower-priority city is chosen. In that respect, I will assume a low-altitude airburst. If they can kidnap and fly three out of four Boeing jets into their intended targets in one day, they can do this as well.

A ground detonation is still entirely possible from inside a hidden building or a ship coming into port (though half the energy of the blast could be directed towards the ocean) and these would be easier operations. But this is primarily a question of what the terrorists believe is desirable and achievable rather than what is easiest.

Target and Environment

Which is the unlucky American city? Certainly, it will be a city and it will be American as far as an Islamic fanatic with an extremely rare and potent weapon is concerned. New York? Los Angeles? San Francisco? New York has had a hard time of it with the two WTC attacks and the downing of flight 587 (yes, I believe it was a terrorist attack), so we may be forgiven for thinking the next attack will happen elsewhere.

However, the Eastern seaboard is the favoured route for bringing in smuggled items and terrorists will not want to spend critical time in long, hazardous journeys westwards. We know that some of the WTC terrorists were based and trained in Florida and that the alleged terrorist on trial just now was caught in the mid-southern state of Oklahoma (ominously he had undertaken Cessna flight training). I suggest that coastal cities further south or even into the Gulf of Mexico may be at greater risk.

Furthermore, a city with a flat topology may be favoured above more contoured cities since hills will deflect and absorb the blast waves as was the case in Hiroshima and Nagasaki attacks. Hiroshima was a flatter city than Nagasaki and paid for this with a greater death toll and destruction per square mile.

Seeking to get the last iota of destructive power out of their devilish device, the terrorists would also favour southern cities because of the hotter conditions and better atmospheric conditions. In other words, clear, sunny skies are better "tinderbox" conditions as would that time of day since Bin Laden would want clear conditions for the infamous mushroom cloud to be recorded by the world's media.

Ultimately, I have no topological maps of southern US cities to make such judgements, but the reader can draw their own conclusions. So far, all this is deductive common sense, but I now move onto the actual effects based on a warm sunny morning in such an American city. The range given in feet and miles will be for the actual distance from ground zero and assumes the fireball centre to be 200 feet above it.


On that fateful morning, the citizens close to ground zero will note the unremarkable drone of a light aircraft flying above their buildings. It is the last thing they ever hear.

Whether the blinding, split second flash of a hundred suns registers with them is unlikely because the intense heat that kills them also travels at the speed of light. As the fireball expands rapidly to its maximum diameter of 460 feet, its centre rages at a temperature of 10,000,000° C for its brief lifetime. Note that temperatures in the WTC attacks were unlikely to have exceeded 5,000° C.

Metallic objects up to 450 feet from ground zero of the initial flash will vaporise. Metallic objects up to 670 feet away will melt. It is needless to guess what happens to people caught out in the open at these ranges — they cease to exist in any meaningful sense of the word and join the raw material for the later fallout.

At 1400 feet from ground zero, rubbers and plastics will ignite and melt whilst wood will char and burn. For victims out in the open, 3rd degree burns are inflicted up to 0.4 miles away, 2nd degree burns up to half a mile away and 1st degree burns at up to nearly a mile away. It is at the extremity of this range that we have the "open oven door effect" which needs no further explanation.


The bomb will expend about 35% of its energy as this radiated heat; a further 50% is absorbed by the atmosphere and becomes a juggernaut blast wave roaring across the city centre at speeds of up to the limit of sound.

Coastal cities used to visiting hurricanes will not have witnessed the boiling winds we describe here. As a comparison, a hefty hurricane-like wind velocity of 116 miles per hour will hit residents at just under half a mile from the blast, whilst those experiencing less damaging winds of 70 mph at under 0.6 miles will feel fortunate.

Meanwhile, those buildings which survived the melting effects of the heat radiation will be finished off by the high winds further into the city centre as winds approaching 670 mph will level or badly damage even steel concrete structures within 740 feet of the blast. No one inside this perimeter can hope to survive unless they are in good underground shelters.

Where the wind speed drops to 380 mph at about 1050 feet, tall multi-storey buildings will be lucky to be left standing and survivors of the heat pulse will suffer potentially fatal lung injuries. As the speed drops to 225 mph at about 1650 feet, most dwelling houses will be wrecked and the streets blocked by debris. Flying fragments become the killer rather than sheer air pressure at these distances.

What the initial radiation pulse did not ignite, the blast does by igniting new fires due to damaged power lines, gas mains and oil tanks. Asphyxiation can also occur at these ranges as much of the air is devoted to fuelling uncontrollable firestorms, which have no mercy on wooden housing.


As I said, this factor will not be so important to devastation-minded terrorists, but the statistics bear witness to further death and misery. The main figure here is the LD-50 dose level which will kill at least 50% of humans exposed to it for an hour or longer. This value is 400 Rads for humans and the victim can die within 30 days. Assuming a weather wind velocity of 15 mph which gives a simple ellipse pattern of fallout, then this lethal dosage can extend downwind for up to several miles but will be confined to a maximum width of only several hundred feet on average.

It is to be noted that an instant gamma ray burst of 400 Rads from the fireball burst will also have this effect up to about 700 feet from ground zero, but the victim would surely be dead from heat and blast effects already.


As the winds drop to gale force at just under a mile, and the glow of the fireball abates, the grim spectacle is over within minutes. We are confronted with a scene of complete devastation within hundreds of feet of ground zero. As the four mile high mushroom cloud silently presides over its work, rescue services will find this a radiation-infested no-go area for months and will concentrate on helping those who have survived further away from ground zero.

Those who are capable of moving will be directed to get out of the immediate area to escape the fallout which is beginning to rain down like snow along the wind patterns of the day. The wreckage on roads as well as every possible vehicle taking to the road at the same time will hamper evacuation procedures as will the transportation of the wounded and infirm.

People located about three-quarters of a mile or more from ground zero will have survived with mainly minor injuries, their immediate task is to play their part in helping friends and relatives to evacuate and beyond that lies the task of rebuilding and repairing homes as well as shattered lives. Though only people in the immediate area of the fallout will be in danger, panic and ignorance will no doubt lead to widespread evacuation across the whole city.

Based on the Hiroshima bombing and scaling down for bomb yields, one could expect fatalities of up to 20,000 and a similar number of injured. If the contours of the land are favourable then these number could drop by half as in the case of Nagasaki. Other factors such as the time of day (e.g. not all people at work yet), accessibility to good medical facilities, evacuation efficiency, and weather conditions all have a large part to play in the final casualty figures.


America is at war with international terrorism and will have to prepare itself against all that its enemies can throw against it. In the larger scheme of things, terrorists can only inflict minimal damage to the American continent as a whole — forty thousand casualties out of nearly 290 million people is 1 in 7250. As a comparison, a resident of the U.S.A. dies every 13 seconds or 20,000 will die of natural and unnatural causes every 3 days.

But these are not the cold-blooded statistics which interest the average citizen. Out of 77 major American cities, they may feel the odds are closer to 1 in 77 rather than 1 in 7250. This is all about psychology and a feeling of security and these terrorists know that only too well.

The protection of Heaven may yet prevent such devices being used, but one suspects that it is more a case of "In the CIA we trust" rather than "In God we trust"!

January 4 , 2002