# How does a 'fire tornado' form?

A 'Fire tornado' or 'Firenado' or 'Fire whirl' are a fearful feature of forest fires world wide. Having seen one up close, I can attest that they are both awesome and utterly terrifying, but I am aware that these vortices are not strictly speaking, actual tornadoes.

An example, filmed in fires in 2012 around Alice Springs, Northern Territory, Australia, as in this YouTube Clip.

The Wikipedia page for this topic rather vaguely states

Often, fire whirls are created when a wildfire or firestorm creates its own wind, which can turn into a spinning vortex of flame.

But, the page does provide the following public domain image of a 'fire tornado':

How does the vortex of fire in a 'fire tornado' form?

• I was waiting for the opportunity to add the firenado tag! Jan 3 '15 at 17:13
• @milancurcic sweet! Awesome that there is a tag for this incredible phenomenom
– user889
Jan 3 '15 at 17:14
• Better known as fire whirl
– Mast
Jan 4 '15 at 14:08
• @Mast, yes, I have mentioned in the question.
– user889
Jan 4 '15 at 15:17

• A firenado documented in Canberra found that the length scale of the firenado was about $L \sim 500$ m, the typical speeds were $U \sim 70$ m s $^{-1}$. If the Coriolis parameter is taken as $f \sim 10^{-4}$, then the Rossby number is $Ro = U/(fL) = 1400$. So Coriolis has negligible influence on the dynamics. Jan 7 '15 at 19:48