Firefighters in California are facing an additional challenge as they contend with the potential for fire tornadoes, a rare but hazardous weather event that can arise from wildfires. The National Weather Service issued a warning indicating that high winds and extremely dry conditions are contributing to a particularly precarious scenario where any new wildfires could quickly become extensive. Although the advisory, effective through Wednesday, did not specifically mention tornadoes, meteorologist Todd Hall remarked that these conditions could indeed lead to the formation of such phenomena.
Simultaneously, researchers in Massachusetts are investigating fire tornadoes in a more controlled environment. They are attempting to replicate this phenomenon on a smaller scale within a laboratory setting, providing a platform for in-depth study.
So, what exactly is a fire tornado? Known by various names such as fire whirl, fire devil, or firenado, the terminology can differ among scientists, firefighters, and the public. Definitions can vary as well; some experts assert that fire whirls are generated purely by heat, while others argue that fire tornadoes also involve clouds created by the fire itself. According to the National Wildfire Coordinating Group, while there is no formal definition for fire tornado, a fire whirl is characterized as a “spinning vortex column of ascending hot air and gases that rises from a fire, lifting smoke, debris, and flames.” Moreover, larger whirls can exhibit intensity akin to small tornadoes.
These whirling phenomena can amplify the strength of a wildfire by drawing in additional air, creating a path of destruction akin to conventional tornadoes. For instance, in 2018, a fire tornado measuring the length of three football fields tragically claimed the life of a firefighter amid an extensive wildfire near Redding, California. This event was noted for an ice-capped cloud that ascended 7 miles into the atmosphere, producing winds that reached up to 143 mph.
Research has further indicated that fire tornadoes can transport embers, known as firebrands, across vast distances, significantly influencing the behavior of a fire. James Urban, an assistant professor at Worcester Polytechnic Institute, highlighted that this capability presents a danger not just to first responders but to anyone in the vicinity, as the fire can change course unpredictably.
The development of fire tornadoes is directly influenced by the interplay between wind patterns, fire plumes, and geographical features. Specialized terrain can occasionally inhibit airflow, setting the stage for a spiral formation to occur.
Innovative research is underway, with facilities like Worcester Polytechnic Institute collaborating with San José State University to delve deeper into this phenomenon. In their laboratory in Worcester, researchers have managed to create small fire tornadoes by strategically surrounding a fire with barriers or by positioning small fires to control airflow. However, these lab-generated tornadoes are significantly smaller than those observed during actual wildfires.
Urban noted that while their institution boasts one of the largest university laboratories dedicated to fire research, replicating the vast fire tornadoes reported in nature is simply beyond their capabilities. Nevertheless, the lab’s experiments do allow for the simulation of spinning fire effects in an enclosed environment, which helps to portray the destructive potential of these weather events.
Overall, the capacity of fire tornadoes to rapidly spread flames and generate hazardous smoke levels, combined with their strong winds, amplifies the risks faced by firefighters. Urban pointed out that observing the emergence of fire tornadoes is a stark indicator of the severity and intensity of the fires raging in California, highlighting the considerable destructive capabilities embedded within these wildfires.
