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 detonations create mass fires or firestorms, which are set simultaneously over very large areas. Unlike ordinary fires, which burn in a line and only have a fraction of a square mile burning at any given time, everything burns at the same time within the area of a firestorm.

The explosion of a 550 kiloton strategic nuclear weapon over a large city, under average weather conditions, can instantly start fires over a total area of about 100 square miles (200 square kilometers). Within minutes after the detonation, enormous volumes of hot air would rise rapidly over the fire zone and created a huge chimney effect, causing incoming air from outside the fire zone to be sucked in towards the fire's center from all directions. These winds would fan the fires, causing them to increase in intensity and spread, generating still larger volumes of hot rising air, which would accelerate the incoming winds to hurricane force.

These superheated, inrushing winds would drive the flames from burning buildings horizontally towards the ground, filling city streets with hot flames and firebrands, and causing the fire to jump hundreds of feet to engulf anything that was not yet violently burning. Average air temperatures in the firestorm would quickly rise to well above the boiling point of water. The entire fire zone would become a huge hurricane of fire from which there would be no escape. Anyone in the streets would be incinerated, and those seeking shelter in basements would either be suffocated or die from the heat. [ NUCLEAR DARKNESS ]