How fire tornados form
What do you get when you cross a fire with a tornado?
These swirling columns of fire and air are a rare and terrifying sight
This apocalyptic-sounding phenomenon occurs when a fire grows large and angry enough to sustain its own weather system. Fierce heat, mixed with turbulent whirlwinds, creates a tornado-like vortex. It sucks ash, embers and flammable gases up into the air, forming a swirling tower of flame called a fire whirl, but also frequently referred to as a fire tornado. These are not considered true tornadoes, however. Unlike a tornado, the vortex of a fire whirl rarely extends all the way from the ground to the clouds, and they form differently.
The most impressive fire tornadoes are forged from wildfires, where they typically reach between 10 and 50 metres in height. Some are born in the plume of a volcanic eruption. Fire whirls are usually transient, fluttering into existence for only a few short minutes before swiftly dying. There are exceptions though: in the Carr Fire of California in 2018, a monstrous three-miletall ‘firenado’ blazed for almost an hour.
Unsurprisingly, these fiery spectacles can be a force of destruction. Fire tornadoes can blaze through natural forests and human-made settlements alike. Sometimes the intense winds lift up burning materials and spit them out elsewhere. This is called ‘spotting’, and it helps wildfires spread.
Fire tornado formation is relatively rare; it relies on a precise balance of extreme temperatures and rapidly changing wind speed or direction. But as a warming climate and poor fire management practices increase the frequency of large wildfires, these conditions could be met more easily in future.