Looking like a twister out of Hell, a giant “fire tornado” was filmed above Idaho’s Soda Fire late last week and has now whipped across the Internet.
“This sucker was shooting flames 100 ft in the air before it passed right in front of the line,” Craig Fluer wrote on Instagram, “all while dropping hot dirt and ash on our helmets.” (See more photos of fire tornados.)
Fire tornadoes are most closely related to dust devils and are distinct from the larger, more powerful tornadoes that develop from the large circulation patterns that can form in supercell thunderstorms. Dust devils form when hot air near the surface rises quickly through a cooler pocket of low-pressure air. As the air rises, it stretches vertically, which drives rotation.
Other hot air rushes in to the bottom of the vortex, and then rises up, intensifying the spinning. In the case of a fire whirl, the fire is what heats the air along the ground in the first place. (Watch a fire tornado in Hungary.)
Fluer filmed the Idaho fire tornado last week. The ongoing wildfire in Idaho has now consumed an estimated 280,000 acres in southwestern Idaho and southeastern Oregon. Dozens of wild horses have perished in the fire, the cause of which is still unknown. Idaho’s state forester has called this year an “unprecedented wildfire season,” spurred by high temperatures and low moisture.
Fire tornados aren’t particularly rare when it comes to big wildfires but they tend to be short—lasting only a few minutes—and they are rarely documented, Jason Forthofer, an engineer with the U.S. Forest Service in Montana, previously told National Geographic.