By: Meteorologist Michael Karow
Updated: Feb 25th 2019

The 2018 Redding Firenado

The 2018 wildfire season in California has set several new records thus far, including the most damages (over $3.5 billion), the most acres burned (over 2 million), and the most fatalities (97 civilians and 6 firefighters). Another superlative of this California wildfire season centers around a destructive fire vortex in the July 2018 Carr Fire, near Redding. A new study published in Geophysical Research Letters posits that this is only the second documented case worldwide of a pyrogenic tornado, or firenado, (with the first documented case in 2003 in Canberra, Australia).

The far more common fire-generated vortices, often seen in pictures and video, are more analogous to dust devils in that they are tied to heating at the surface and don’t extend to a cloud base. The Carr Fire, like the 2003 Canberra fire event, generated a pyrocumulonimbus cloud that extended as high as 12 km (over 7 miles). The updraft of this cloud helped to stretch the underlying column of air, which already had a zone of cyclonic wind shear near the surface. This lifting and stretching of the rotating column of air helped to concentrate the rotation at the surface, eventually leading to tornado-strength winds, estimated at 143 mph, or EF-3 strength.  

Although not forming like a classic tornado (developing from the rotating mesocyclone of a supercell thunderstorm), both the 2003 Canberra and 2018 Redding firenado events still are technically tornadoes, just tornadoes of the “landspout” variety.

fire whirl devil
Small fire whirl, or "fire devil"
2018 Redding Firenado Tornado
2018 Redding Firenado [CalFire]
Carr pyrocumulonimbus firenado
3D visualization of the Carr Fire pyrocumulonimbus cloud and firenado [Lareau 2018]