Initially starting as a controlled burn in Adams County, Colo., on Friday, March 14, 2014, firefighters caught a glimpse of a rare, highly unpredictable weather phenomenon known as a firenado.
A swirling rotation of smoke, gas and debris, a firenado is generated when an active fire is swept upwards by strong winds, creating a vortex.
"The heat of the fire rising through the air allows the vortex to strengthen and create the firenado," AccuWeather Meteorologist Eric Leister said. "The firenado can then suck more brush and debris into itself and fuel the fire further."
Firenadoes can be extremely dangerous, as they have the ability to throw burning embers miles away. They are usually between five and 10 stories high and can measure up to 10 feet wide.
While this rarity lasts usually only minutes, the largest firenadoes have been known to create winds topping 100 mph.