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If a nuclear warhead detonated above midtown Manhattan?

What would happen if an 800-kiloton nuclear warhead detonated above midtown Manhattan? Bulletin of the Atomic Scientists, 25 Feb 15  Steven StarrLynn EdenTheodore A. Postol Russian intercontinental ballistic missiles are believed to carry a total of approximately 1,000 strategic nuclear warheads that can hit the US less than 30 minutes after being launched. Of this total, about 700 warheads are rated at 800 kilotons; that is, each has the explosive power of 800,000 tons of TNT. What follows is a description of the consequences of the detonation of a single such warhead over midtown Manhattan, in the heart of New York City.

The initial fireball. The warhead would probably be detonated slightly more than a mile above the city, to maximize the damage created by its blast wave. Within a few tenths of millionths of a second after detonation, the center of the warhead would reach a temperature of roughly 200 million degrees Fahrenheit (about 100 million degrees Celsius), or about four to five times the temperature at the center of the sun.

A ball of superheated air would form, initiallly expanding outward at millions of miles per hour. It would act like a fast-moving piston on the surrounding air, compressing it at the edge of the fireball and creating a shockwave of vast size and power.

After one second, the fireball would be roughly a mile in diameter. It would have cooled from its initial temperature of many millions of degrees to about 16,000 degrees Fahrenheit, roughly 4,000 degrees hotter than the surface of the sun.

On a clear day with average weather conditions, the enormous heat and light from the fireball would almost instantly ignite fires over a total area of about 100 square miles.

Hurricane of fire. Within seconds after the detonation, fires set within a few miles of the fireball would burn violently. These fires would force gigantic masses of heated air to rise, drawing cooler air from surrounding areas toward the center of the fire zone from all directions.

As the massive winds drove flames into areas where fires had not yet fully developed,the fires set by the detonation would begin to merge. Within tens of minutes of the detonation, fires from near and far would joinhave formed a single, gigantic fire. The energy released by this mass fire would be 15 to 50 times greater than the energy produced by the nuclear detonation……….

No survivors. Within tens of minutes, everything within approximately five to seven miles of Midtown Manhattan would be engulfed by a gigantic firestorm. The fire zone would cover a total area of 90 to 152 square miles (230 to 389 square kilometers). The firestorm would rage for three to six hours. Air temperatures in the fire zone would likely average 400 to 500 degrees Fahrenheit (200 to 260 Celsius).

After the fire burned out, the street pavement would be so hot that even tracked vehicles could not pass over it for days. Buried, unburned material from collapsed buildings throughout the fire zone could burst into flames when exposed to air—months after the firestorm had ended.

Those who tried to escape through the streets would have been incinerated by the hurricane-force winds filled with firebrands and flames. Even those able to find shelter in the lower-level sub-basements of massive buildings would likely suffocate from fire-generated gases or be cooked alive as their shelters heated to oven-like conditions.

The fire would extinguish all life and destroy almost everything else.Tens of miles downwind of the area of immediate destruction, radioactive fallout would begin to arrive within a few hours of the detonation.

But that is another story.

Editor’s note: This article is adapted from “City on Fire” by Lynn Eden, originally published in the January 2004 issue of the Bulletin of the Atomic Scientists. http://thebulletin.org/what-would-happen-if-800-kiloton-nuclear-warhead-detonated-above-midtown-manhattan8023

February 27, 2015 - Posted by Christina Macpherson | USA, weapons and war