Fire tornadoes are a rare weather phenomenon induced by a combination of fire and wind. Also known as “Fire Devils’, they occur when intense rising heat and turbulent winds conditions combine to form whirling eddies of air. We have not heard more about fire tornadoes because they form in situations most of us try to avoid. Situations like wildfires. They are considered as some of the most violent natural events on Earth. A fire tornado in Peshtigo, Wisconsin in 1871 burnt 6,070 square km (1.5 million acres) and caused human casualties too.
On a positive note, fire tornadoes only last for short span. As the hot air ascends and cools, its strength subsides, and whatever fuel that powers the fire devil will then burn out. (Source)