PBS has published a 10-minute video (below) about how fire whirls and fire tornados form. Here is how they summarize it:
A fire tornado, or “firenado,” is exactly what it sounds like: a tornado made out of fire… and it is truly the stuff of nightmares. The most famous example occurred when the 2018 Carr Fire spawned an EF3 fire tornado with estimated wind speeds of 143 mph! And as climate change drives increasing wildfires around the planet, it only makes sense that we see more fire tornadoes as well.
Tune into this episode of Weathered to learn what the latest science can tell us about these rare but dangerous phenomena as well as about the surprising ability of burnt forests to store carbon and mitigate climate change.
Weathered is a show hosted by meteorologist Maiya May and produced by Balance Media that helps explain the most common natural disasters, what causes them, how they’re changing, and what we can do to prepare.
Fire whirls, much like dust devils, are not uncommon on a fire when the atmosphere is unstable, and are much smaller than fire tornados. In 1978 a researcher for the National Weather Service in Missoula, David W. Goens, established parameters for the two.
He said the average size of a fire whirl is usually 33 to 100 feet, with rotational velocities of 22 to 67 MPH.
But a fire tornado dominates the large scale fire dynamics. They lead to extreme hazard and control problems. In size, they average 100 to 1,000 feet in diameter and have rotational velocities up to 90 MPH.
Shame….Clive Countryman – Fire Whirls: Why, when and where. 1971. Not some meteorologist guy. The greatest fire scientist of the 20th century!
Wicked videos! Just unbelievable.
The technical difference between the 2 that separate them as explained to me by a meteorologist is that a tornado forms in the sky and drops to the ground. A fire whirl starts at the ground and rises to the sky. They are created by similar weather influences but in opposing locations. That’s why it can’t be truly called a ‘fire ado’ as media likes to plug it. No argument tho on the destructive power and danger posed to resources.
New evidence has challenged the idea that tornados form above the ground and descend to the ground. See here for example:
https://www.kut.org/texas/2018-12-28/where-do-tornadoes-get-their-start-maybe-its-not-all-about-the-funnel-cloud