A very strong tornado of smoke and fire spun up along the edge of Idaho’s Soda Fire late last week, captured on video by one of the people there to help control the blaze.

Craig Fluer was fighting the Soda Fire in extreme conditions late last week when he caught this incredible video. “This sucker was shooting flames 100 ft in the air before it passed right in front of the line,” Fluer wrote on Instagram, “all while dropping hot dirt and ash on our helmets.”

Fire whirls — or “firenadoes” — form when heat from the wildfire causes air to rise rapidly. In these areas of turbulent winds the updrafts can spin and gain momentum, developing into a full, fiery, tornado-like whirl that can hurl 2,000-degree debris into the air.

It’s possible the core of the firenado was actually on fire, though there’s so much black smoke and debris outside the core that it’s impossible to tell. Often as the whirls sucks up flammable debris from the ground they will ignite, fueled by the oxygen-rich air above the ground.

As of Tuesday morning the Soda Fire, which as been burning southwest of Boise since Aug. 10, was 90 percent contained thanks to the incredible efforts the 700-person fire management team. The Soda Fire burned over 280,000 acres in the eight days since it began.

More fire whirls: