The Carr fire burns along Highway 299 between Whiskeytown and Redding, July 28, 2018.
The Carr fire burns along Highway 299 between Whiskeytown and Redding, July 28, 2018. ZUMA Press, Inc./Alamy

On the evening of July 26, California’s Carr fire, one of the most destructive fires in the state’s history, was burning in Redding, when conditions aligned to create a massive whirl of smoke and fire. It lasted for an hour and a half, and the people who caught it on video called it the “Firenado.”

On Thursday, the National Weather Service said that, according to preliminary information, the winds of the column were moving at speeds of 143 mph, classifying it as an EF-3 tornado on the Enhanced Fujita scale, which rates tornado intensity on a range of zero to five.

The heat of wildfires can sometimes create short-lived “fire whirls,” and at first, experts were reluctant to call the Redding fire column a tornado. But given its strength and how it was formed, some are now calling it a “fire tornado.”

Vegetation in California is deadly dry, and the Carr fire has been burning unusually hot. When it reached Redding, a plume of smoke rose 20,000 feet into air, before hitting a cap in the atmosphere, a set of conditions that kept it from rising further. But when two plumes broke through, that created an fast-moving updraft, conditions similar to those of tornado formation.

The “firenado” also left behind damage that looked more like the work of a tornado than a wildfire—tiles stripped from roofs, trees uprooted, cars moved, a transmission tower tipped over. If it is considered a tornado, this destructive whirl would be the most powerful in California’s history.