Scientists are learning more about fire tornadoes and the spinning funnels of flame
Zoomen this image to toggle caption Erica Zurek/Montana Public Radio Erica Zurek/Montana Public Radio
Climate change is driving wildfire seasons to be longer and more intense. When fires grow large enough, they can also create extreme weather. This weather can create large funnels of smoke and flame known as "fire tornadoes". However, it is still unclear what the connection is between West's increasing severe fires and those tornadoes.
Late June saw footage of firefighters fighting the Tennant Fire in Northern California go viral.
A Facebook video shows a funnel cloud glowing from flames. It looks almost like a tornado or a dust devil. The swirling smoke, wind, and flame looks almost apocalyptic.
Jason Forthofer is a Montana firefighter and mechanical engineer with the U.S Forest Service's Missoula Fire Sciences Lab. He said that funnels such as this one are known as "fire whirls". He explained that the difference between tornadoes and whirls is just a matter of proportion.
He said that fire tornadoes are "more of that, the bigger version of a firewhirl and they really are the same size and scale as a regular tornado."
Forthofer suggested that the reason why there are so many images and videos of the Tennant Fire is that people keep better track of them.
He said that it was more likely to capture them now, as everyone has a smartphone and carries a camera with them everywhere.
He said that although the data is too new to know for certain, it is possible that fire tornadoes are more common as fires become more intense and conditions that make them more frequent.
Heat, rotating air and conditions that make fire whirls stronger are the ingredients.
Forthofer is able to simulate these ingredients in a laboratory chamber. He walks towards a 12-foot-tall empty tube, pours alcohol in its bottom, then uses a lighter to light the flames.
The tube is filled with a spinning funnel of fire that measures about one foot in diameter. It then shoots upwards.
It's difficult to know how often fire whirls and tornadoes have occurred in the past because they are common in remote locations with no one else around. Forthofer searched for them and found evidence of fire tornadoes back in 1871, when devastating fires struck Chicago and Wisconsin.
Forthofer stated, "I realized these gigantic tornado-sized fire whirls (let's call them that) happen more often than we thought and a lot of firefighters didn’t even realize that that was even possible."
Julie Malingowski, National Weather Service Meteorologist, said that fire tornadoes are not common but can happen. She provides weather updates to firefighters during wildfires. This can be vital information that could save lives. She stated that the most important daily factors that influence fire behavior are wind, heat, and relative humidity. These factors are much more common than spinning flames.
Malingowski stated that "everything the fire does, as far as spreading, as soon as it breaks out," was dependent on the weather.
Researchers are also studying extreme weather patterns caused by fires. For example, fire-generated thunderstorms are known as pyrocumulonimbus cloud, or pyroCBs. These thunderstorms can create dangerous conditions for fire behavior, including the necessary conditions for fire tornadoes.
Michael Fromm, a meteorologist from the Naval Research Lab, Washington, D.C., stated that although the data only goes back a decade, the total number of PyrcoCBs produced in North America this year exceeds any year in the dataset.
He said, "And the fire season hasn't even ended yet."
