Yahoo News explains: What is a fire tornado?

Officials say the raging Northern California wildfire has claimed the lives of firemen and civilians. It has also scorched more than 150,000 acres and destroyed more than 1,500 structures.

In late July in the midst of the record-breaking wildfire, a powerful spinning vortex emerged that rose 18,000 feet in the air, with wind speeds exceeding 143 mph, and lasted for an hour and a half.

The National Weather Service called it a “large fire whirl.” They define it as “a rotating column of fire induced by intense heat and turbulent winds.”

Other weather scientists say it’s fair to call it a fire tornado because of its strength and destructiveness.

What is a fire tornado?

The scientific phenomenon can form from extreme temperatures like the ones northern California is experiencing from the wildfires.

When the hot air rises above the fire, more fresh, oxygenated air rushes in. The column of air above the fire can then start to rotate much like a tornado. Officials say the northern California fire has destroyed more than 1,000 homes, making it the sixth most destructive fire in the state’s history.