When the right kind of fire and wind collide, a terrifying twister of spinning and climbing flames can materialize. Scientists typically call this a fire whirl, but the phenomenon goes by many names, like fire tornado, fire devil, or dragon twist. Whatever you call it, its high intensity and destructive power remain the same. On Sunday, one was captured on camera by firefighters in British Columbia who struggled to fight the blazing vortex.
Mary Schidlowsky, a wildland firefighter and paramedic, posted a video of this fire tornado on Instagram. In her caption, she notes that it grew to over 200 feet tall, although the smoke obscures what viewers can actually see. Schidlowsky writes:
“Fire tornado destroyed our line. It threw burning logs across our guard for 45 minutes and pulled our hose 100 plus ft. in the air before melting it. That’s definitely a first.”
While fire tornados, or whirls, aren’t that rare, it is uncommon to catch one on camera. In a 2011 article in the Journal of Combustion, USDA Forest Service scientists explain that “with their sudden formation, erratic movement, and often sudden dissipation,” fire whirls are a “good example of extreme fire behavior.”
Fire whirls are dynamically related to other swirling atmospheric phenomena like dust devils, waterspouts, and tornados. While fire whirls can vary in their location, scientists from the University of Maryland determined in 2017 that there are three criteria essential for the formation of all whirls: a fire source, a swirling mechanism like wind, and a friction force at the bottom for boundary layer formation. What really sets fire whirls apart from other fires is the rotation of fluid particles around their center of mass. We can see them because of the flames, ash, and embers that get whipped up within this spiral of wind and gas.
In lab experiments, scientists confirmed that the spinning core within the whirl can reach a maximum vertical velocity of 91 meters per second. Their tall, slender appearance is the result of the rotational motion of the whirl’s core. This movement reduces the power of convective motion within the core, allowing the whirl to sustain its intensity. As heat is lifted on buoyant air, and the gas that surrounds the flames encloses it, the air inside the whirl gains strength. Through a process of tilting and stretching, a fire whirl picks up velocity and evolves into a powerful force.
While fire whirls have been in the news in recent years because of their devastating effects in California, they are not specific to wildfires. Although all of them are intensely rotating columns of gas found near flames, they range in locational diversity and have been observed within urban fires, oil spill fires, and alongside volcanic eruptions. For example, the Great Chicago Fire of 1871 was particularly destructive because of whirlwinds within it, which contributed to its massive spread throughout the city. In 1921 a 7.9-magnitude earthquake hit Tokyo, Japan and caused a massive urban fire, which then spawned a whirl that killed an estimated 38,000 people in less than 15 minutes.
CBC reports that this fire in British Columbia was caused by heat rising off the wildfire and combining with extremely high winds. While the firefighters stick near it to deal with its power, the best thing for most people to do when they see a fire whirl is to run away.