Mechanism-

A firestorm is created as a result of the stack effect as the heat of the original fire draws in more and more of the surrounding air. This draft can be quickly increased if a low level jet stream exists over or near the fire. As the updraft mushrooms, strong gusty winds develop around the fire, directed inward which supply the fire with additional air. This would seem to prevent the firestorm from spreading on the wind, but the tremendous turbulence also created causes the strong surface inflow winds to change direction erratically. This wind shear is capable of producing small tornado- or dust devil-like circulations called fire whirls which can also dart around erratically, damage or destroy houses and buildings, and quickly spread the fire to areas outside the central area of the fire. A firestorm may also develop into a mesocyclone and induce true tornadoes. Probably, this is true for the Peshtigo Fire.

The greater draft of a firestorm draws in greater quantities of oxygen, which significantly increases combustion, thereby also substantially increasing the production of heat. The intense heat of a firestorm manifests largely as radiated heat (infrared radiation) which ignites flammable material at a distance ahead of the fire itself. This also serves to expand the area and the intensity of the firestorm. Violent, erratic wind drafts suck movables into the fire, while people and animals caught close or under the fire die for lack of available oxygen. Radiated heat from the fire can melt asphalt, metal, and glass, and turn street tarmac into flammable hot liquid. The very high temperatures replicate the conditions of a smelting furnace,where anything that might possibly burn does so readily, until the firestorm runs out of fuel.

Besides the enormous ash cloud produced by a firestorm, under the right conditions, it can also induce condensation, forming a pyrocumulus cloud or "fire cloud". A large pyrocumulus can grow into a pyrocumulonimbus and produce lightning, which can set off further fires. Apart from forest fires, pyrocumulus clouds can also be produced by volcanic eruptions.

In Australia, the prevalence of eucalyptus trees that have oil in their leaves results in forest fires that are noted for their extremely tall and intense flame front. Hence the bush fires appear more as a firestorm than a simple forest fire. Sometimes, emission of combustible gases from swamps (e.g., methane) has a similar effect. For instance, methane explosions enforced the Peshtigo Fire.

Yellow Fires-

The Yellowstone fires of 1988 together formed the largest wildfire in the recorded history of theU.S.'s Yellowstone National Park. Starting as many smaller individual fires, the flames spread quickly out of control with increasing winds and drought and combined into one large conflagration, which burned for several months. The fires almost destroyed two major visitor destinations and, on September 8, 1988, the entire park was closed to all non-emergency personnel for the first time in its history. Only the arrival of cool and moist weather in the late autumn brought the fires to an end. A total of 793,880 acres (3,213 km²), or 36 percent of the park was affected by the wildfires.Thousands of firefighters fought the fires, assisted by dozens of helicopters and fixed-wing aircraftwhich were used for water and fire retardant drops. At the peak of the effort, over 9,000 firefighters were assigned to the park. With fires raging throughout the Greater Yellowstone Ecosystem and other areas in the western United States, the staffing levels of the National Park Service and other land management agencies were inadequate to the situation. Over 4,000 U.S. military personnel were soon assisting in fire suppression efforts. The fire fighting effort cost $120 million ($240 million as of 2012). No firefighters died while fighting the fires in Yellowstone, though there were two fire-related deaths outside the park.

Before the late 1960s, fires were generally believed to be detrimental for parks and forests, and management policies were aimed atsuppressing fires as quickly as possible. The beneficial ecological role of fire became better understood in the decades before 1988, and a policy of allowing natural fires to burn under controlled conditions had been highly successful in reducing the area lost annually to wildfires. However, by 1988, Yellowstone was overdue for a large fire, and, in the exceptionally dry summer, the many smaller "controlled" fires combined. The fires burned discontinuously, leaping from one patch to another, leaving intervening areas untouched. Large firestorms swept through some regions, burning everything in their paths. Tens of millions of trees and countless plants were killed by the wildfires, and some regions were left looking blackened and dead. However, more than half of the affected areas were burned by ground fires, which did less damage to hardier tree species. Not long after the fires ended, plant and tree species quickly reestablished themselves, and natural plant regeneration has been highly successful.

The Yellowstone fires of 1988 were unprecedented in the history of the National Park Service, and many questioned existing fire management policies. Media accounts of mismanagement were often sensational and inaccurate, sometimes wrongly reporting that most of the park was being destroyed. While there were temporary declines in air quality during the fires, no adverse long-term health effects have been recorded in the ecosystem. Contrary to initial reports, few large mammals were killed by the fires, though there has been a reduction in the number ofmoose which has yet to rebound. Losses to structures were minimized by concentrating fire fighting efforts near major visitor areas, keeping property damage down to $3 million ($6 million as of 2012).

Thermal Column-

A thermal column (or thermal) is a column of rising air in the lower altitudes of the Earth's atmosphere. Thermals are created by the uneven heating of the Earth's surface from solar radiation, and are an example of convection, specifically atmospheric convection. The Sun warms the ground, which in turn warms the air directly above it.Dark earth, urban areas and roadways are good sources of thermals.

The warmer air expands, becoming less dense than the surrounding air mass. The mass of lighter air rises, and as it does, it cools due to its expansion at lower high-altitude pressures. It stops rising when it has cooled to the same temperature as the surrounding air. Associated with a thermal is a downward flow surrounding the thermal column. The downward moving exterior is caused by colder air being displaced at the top of the thermal.

The size and strength of thermals are influenced by the properties of the lower atmosphere . Generally, when the air is cold, bubbles of warm air are formed by the ground heating the air above it and can rise like a hot air balloon. The air is then said to be unstable. If there is a warm layer of air higher up, aninversion can prevent thermals from rising high and the air is said to be stable.

Thermals are often indicated by the presence of visible cumulus clouds at the apex of the thermal. When a steady wind is present thermals and their respective cumulus clouds can align in rows oriented with wind direction, sometimes referred to as "cloud streets" by soaring andglider pilots. Cumulus clouds are formed by the rising air in a thermal as it ascends and cools, until the water vapor in the air begins tocondense into visible droplets. The condensing water releases latent heat energy allowing the air to rise higher. Very unstable air can reach the level of free convection (LFC) and thus rise to great heights condensing large quantities of water and so forming showers or even thunderstorms.

Firebombing-

Firebombing is a technique designed to damage a target, generally an urban area, through the use of firecaused 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 and the high explosives disrupt the ability of firefighters to douse the fires.

Although simple incendiary bombs have been used to destroy buildings since the start of gunpowder warfare, World War II saw the first use of strategic bombing from the air to destroy the ability of the enemy to wage war. London, Coventry and many other British cities were firebombed during the Blitz. Most large German cities were extensively firebombed starting in 1942 and almost all large Japanese cities were firebombed during the last six months of World War II. However as Sir Arthur Harris, the officer commanding RAF Bomber Command from 1942 through to the end of the war in Europe, pointed in his post war analysis, although many attempts were made to create deliberate man made firestorms during World War II few attempts succeed:

"The Germans again and again missed their chance, ...of setting our cities ablaze by a concentrated attack. Coventry was adequately concentrated in point of space, but all the same there was little concentration in point of time, and nothing like the fire tornadoes of Hamburg or Dresden ever occurred in this country. But they did do us enough damage to teach us the principle of concentration, the principle of starting so many fires at the same time that no fire fighting services, however efficiently and quickly they were reinforced by the fire brigades of other towns could get them under control."