Fire whirls occur when a wildfire, or especially firestorm, creates its own wind, which can spawn large vortices. Even bonfires often have whirls on a smaller scale and tiny fire whirls have been generated by very small fires in laboratories. ... They form when a warm updraft and convergence from the wildfire are present.

Where are fire whirls most common?

In nature, fire whirls are most often observed in mass fires. These include both large wildland (also known as forest fires or bushfires) and urban conflagrations, such as the burning of cities or towns.

How does fire help create fire whirls and tornadoes?

As smoke rises and condenses in the upper atmosphere, it forms an ice-topped cloud known as a pyro-cumulonimbus or firestorm cloud over the fire vortex. The development of the cloud stretches the underlying column of air, concentrating the rotation near the surface and causing winds to accelerate to tornado strength.