A wildfire needs three elements to start: fuel, oxygen and a heat source — what firefighters call the fire triangle.
A flash drought provided the fuel. Strong winds from a passing hurricane supplied the oxygen. A powerline downed in dry grass took care of the rest.
Wildfires engulfed the historic oceanfront town of Lāhainā, Hawaii, on August 8th, 2023, spreading through homes, apartments and city streets. Many residents fled by car or sought refuge in the ocean. Others weren’t as lucky. The confirmed death toll is 115, and 66 people remain missing as of this writing.
Russia, Greece, Spain, Portugal — now Maui, Hawaii, is the latest area to be impacted by the 2023 wildfire season. Across the world, boreal forests are being devastated by the worst wildfires in recorded history. The science of wildfire behavior is terrifying but may yield answers engineers can use to control this destructive force of nature.
The Science of Wildfires Explained
Wildfires can burn millions of acres of land at a speed of up 6 miles per hour in forests or 14 miles per hour in grasslands, faster if traveling uphill. (For comparison, the average human runs between 6.5 and 8 miles per hour.) Fire doubles in speed with every 10 degrees of slope. As if that weren’t enough, wildfire flames can reach one meter in height and temperatures in excess of 800 degrees Celsius (1,472 degrees Fahrenheit).
Wildfires near populated areas pose a substantial risk to homes, lives and wildlife, especially if there’s no advanced warning — and Lāhainā residents had little to no warning. Maui officials did not sound sirens alerting residents to the advancing wildfire, as sirens in Hawaii are used to warn of tsunamis. Officials feared that upon hearing the siren, people would have gone mauka (to the mountainside) toward certain death.
Wildfire can kill via direct burns and can cause building collapse and explosions from gas stations, for instance. Survivors lucky enough to escape with their lives can succumb to infection. Still, the number one cause of death from fires is smoke inhalation.
Where There’s Smoke …
Wildfire smoke is a toxic mixture of pollutants, such as fine particulate (PM 2.5): a mix of airborne microscopic solid and liquid particles that can become lodged deep in the lungs. Asthma attacks, heart attacks and strokes can follow. Carbon monoxide (CO) is another theat. Colorless and odorless, CO can kill within minutes of inhalation, entering the bloodstream and preventing oxygen from reaching vital organs.
Global Warming and Wildfires
Wildfires, you’ll recall, require fuel. Climate change is creating warmer and dryer conditions, leading to longer and more active fire seasons. Severe drought and high temperatures are creating all the fuel wildfire needs in the form of dead trees, shrubs and grasses.
Lightning is yet another concern. With every degree Celsius (two degrees Fahrenheit) of global warming, lightning strikes increase by 12%. Worse yet, wildfires release stored carbon into the atmosphere when they burn forests to the ground, worsening climate change and continuing the cycle. Unless we can find a way to turn down the world’s thermostat, wildfires will only become more frequent and severe.
UT Fire Research Group Work to Preserve a Delicate Balance
Wildfires are historically beneficial for clearing underbrush, releasing nutrients into the soil and allowing sunlight to reach forest floors. Unfortunately, the prevention of naturally occurring forest fires has led to an influx of high-intensity wildfires.
The UT Fire Research Group, led by Dr. Ofodike Ezekoye, is working to reestablish this delicate balance.
Some of the team’s most interesting research focuses on wildland firebrands: burning particles that float through the air and have the potential to spread fire to homes. (Firebrand is also a term used to refer to people who passionately promote a cause.) The team created consistent embers to better understand the ignition behavior of various flame-retarded insulation materials.
Another experiment looked at the physics and fire dynamics of grassland-fueled fires. Researchers selected Bluestem grass, prevalent throughout Texas, as the fuel and observed how fire spread from one plant to another. Studying heat flux and mass loss, researchers hope to better predict fire behavior and develop mitigation strategies that can save lives.
Looking to the Future of Fire Prevention
“Should we have invested more in fire prevention? Of course, of course. But we’d never had a fire of this consequence,” said Hawaii Governor Josh Green. Wildfires continue to emerge, even as rescuers comb through the Maui wreckage. Wildfires knocked out power to an entire California county a little more than one week after the Maui disaster. Wildfires will continue to grow both in frequency and severity, and UT Austin engineers will continue studying the science of wildfires to find a solution.
Mechanical Engineering at UT Austin
Mechanical engineers must contend with the destructive force of fire if they hope to harness its energy. If you’re interested in learning how to maintain this balance, consider The University of Texas at Austin and its 100% online MS in mechanical engineering program.
Directed by Professor Ezekoye of the UT Fire Research Group, our online program explores essential engineering topics including heat transfer and applied thermodynamics. Study on your schedule, gain specialized knowledge and learn what it takes to be an industry leader, all in as little as two years.
Become a firebrand for mechanical engineering. Apply now to our 100% online master’s degree in mechanical engineering program.
Sources:
https://www.nationalgeographic.com/environment/article/wildfires
https://www.lung.org/blog/how-wildfires-affect-health
https://nhmu.utah.edu/sites/default/files/attachments/Wildfire%20FAQs.pdf
https://www.noaa.gov/noaa-wildfire/wildfire-climate-connection
