Firebombing, Firestorms and Nuclear Weapons

A firestorm is a conflagration which attains such intensity that it creates and sustains its own wind system. It is most commonly a natural phenomenon, created during some of the largest bushfires and wildfires. Firestorms resulting from the bombardment of urban areas in the Second World War were generally confined to the areas initially seeded with incendiary devices, and the firestorm did not appreciably spread outward. A firestorm may also develop into a mesocyclone and induce true tornadoes/fire whirls. This occurred with the 2002 Durango fire, and probably with the much greater Peshtigo Fire.

Unlike the highly combustible World War II cities that firestormed from conventional and nuclear weapons, a FEMA report suggests that due to the nature of modern U.S. city design and construction, a firestorm is unlikely to occur even after a nuclear detonation because highrise buildings do not lend themselves to the formation of firestorms because of the baffle effect of the structures, and firestorms are unlikely in areas whose modern buildings have totally collapsed, with the exceptions of Tokyo and Hiroshima, because of the nature of their densely-packed “flimsy” wooden buildings in World War II. US suburbs ten to have six houses per acre, this means suburbs are not densely built enough to create a firestorm even if every house was burning.

Nuclear weapons produce effects that are in the reverse order, with thermal effects and “flash” occurring first, which are then followed by the slower blast wave. It is for this reason that conventional incendiary bombing raids are considered to be a great deal more efficient at causing mass fires than nuclear weapons of comparable yield.

Conventional weapon firebombing is a technique designed to damage a target, generally an urban area, through the use of fire, caused by incendiary devices, rather than from the blast effect of large bombs. Such raids often employ both incendiary devices and high explosives. The high explosive destroys roofs, making it easier for the incendiary devices to penetrate the structures and cause fires. The high explosives also disrupt the ability of firefighters to douse the fires.

It has been estimated that the same fire ferocity and damage produced at Hiroshima by one 16-kiloton nuclear bomb from a single B-29 could have instead been produced by about 1,200 tons/1.2 kilotons of incendiary bombs from 220 B-29s distributed over the city.

Nagasaki, a single 21 kiloton nuclear bomb dropped on the city could have been estimated to be caused by 1,200 tons of incendiary bombs from 125 B-29s.

City fire damage is largely dependent not on the yield of the weapons used, but on the conditions in and around the city itself, with the fuel loading per square meter value of the city being one of the major factors. The Great Fire of London in 1666- London in 1666 was a densely packed place with predominantly wooden and thatch building construction. It was a citywide mass fire started from one domestic fireplace. The largest nuclear weapon conceivable will be incapable of igniting a city into a firestorm if the city’s properties, namely its fuel density, are not conducive to one developing. Nagasaki had fires but did not have a firestorm despite being hit with a larger bomb than Hiroshima.

Nuclear weapons do not add any fuel to a city, and fires are entirely dependent on what was contained in the city prior to bombing, in direct contrast to the incendiary device effect of conventional raids.

There could be a physical limitation for air to penetrate more than half a mile or one mile into a citywide firestorm.

Here is an online copy of the “Exploratory Analysis of Firestorms”

India Nuclear Weapons

Pakistan Nuclear Weapons

On the basis of the sizes of weapons tested by Pakistan in 1998, it is estimated that the current weapons have yields of 5 to 12 kilotons. Pakistan has produced tactical nuclear weapons for use on battlefields to counter the conventional weapons advantage of an invading Indian army. Their current arsenal probably includes 24 tactical weapons of unknown yield, but perhaps in the range of 5 to 12 kt .

US, Russia and China nuclear weapons

China has reportedly increased its nuclear weapons from about 200 in 2021 to about 400 today. China mostly has land based ICBMs. The DF-41 has 6-10 MIRV w/yields of 20, 90, 150 or 250 kt. It is usually better to make ten 20 kiloton nukes than on 250 kt. Land based ICBMs are generally believed to be more vulnerable to an opponent first strike. China is using stronger modern cement and multiple silos to make it more difficult to destroy all of the nukes. Chnia has a lot of submarines. US submarine nukes are 90 kiloton missiles.