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. The Black Saturday bushfires, the Great Peshtigo Fire and the Ash Wednesday fires are examples of firestorms, as is that following the 1906 San Francisco Earthquake. Firestorms can also be deliberate effects of targeted explosives such as occurred as a result of the aerial bombings of Hamburg, Dresden, and the atomic bombing of Hiroshima.
Read more about Firestorm: Mechanism, City Firestorms, Nuclear Weapon Induced City Firestorms in Modern Cities