Oregon Firefighters Catch 'Firenado' on Video

— -- Firefighters in Oregon captured video of a "firenado" as they were battling a field fire that torched nearly seven acres of farmland in Cornelius, about 20 miles west of Portland.

On Friday afternoon, the Cornelius Fire Department responded to a 2-alarm blaze that quickly became a whirl of fire. It took firefighters about an hour to extinguish the flames.

The fire appeared to have been started by farming equipment that was being used to cut the field, firefighters said. No structures were damaged and no one was injured, but the fire department asked that residents limit their outdoor work due to the high temperatures and low humidity in the area.

A firenado is formed when ground-level winds come in contact with fire and whip it into the air, creating a spiral of bright red and orange. Firenadoes are difficult for firefighters to battle, as the tunnels suck in burning debris and can spit embers miles away, enlarging a wildfire's path of destruction. Usually the phenomenon only lasts minutes.