Fires can be extremely destructive and deadly, but some types of fire are more dangerous than others.
“Flash fires,” defined as fires that grow at least six square miles in a single day, are the most dangerous form of wildfire, causing more damage than most other fires.
NASA images taken by Moderate Resolution Imaging Spectroradiometer (MODIS) sensors on the Aqua and Terra satellites reveal how much land a fast fire can cover in a single day, showing the growing extent of the March 2017 Northwest Oklahoma Complex fires that were started by a lightning strike.
Between March 6 and March 7, these fires — including the Starbuck, 283, Selman and Beaver fires — grew by up to 827 square miles in a single day.
After dryness and strong winds, the flames spread to the prairie, with the fire complex eventually growing to an area nearly as large as Rhode Island, killing 4,000 cattle and 8 people, and destroying 151 structures.
According to a magazine article Sciencebetween 2001 and 2020, fast-moving fires accounted for only three percent of all U.S. wildfires, but were responsible for 89 percent of all wildfires.
Fast-moving fires were also found to account for 66 percent of all fire deaths, 78 percent of structures destroyed, and $18.9 billion in suppression costs.
This means that fast fires are much more dangerous than many large “mega-fires”.
“We focused on the wrong metric,” study co-author Jennifer Balch, director of the Environmental Data Science Innovation & Inclusion Lab at the University of Colorado Boulder, said in a statement. “The rate of fire really matters.
Flash fires are usually driven by strong winds and often occur in grasslands in the fall when vegetation is particularly dry. Strong winds can carry embers far ahead of the main fire – causing a re-ignition – as well as fan flames to increase their intensity.
National Weather Service
Rapid fires can cover large areas in a short amount of time, making them particularly dangerous and difficult to control.
“When you have extreme wind events, fires can become out of control,” Michael Falkowski, NASA’s wildland program manager, said in a statement. “For safety reasons, the firefighters have to move out of the way.”
The 2020 Labor Day fires in Oregon and Washington burned as much land in two weeks as has burned in the past 50 years.
According to Science paper, rapid fires appear to be getting faster, with California fires growing 398 percent faster in 2020 than in 2001.
“During this period, nearly 3 million structures were located within 4 kilometers of a fast-moving fire in the US,” the researchers wrote in the paper.
This increase in fire rates may be due to climate change causing warmer temperatures, stronger winds and drier vegetation, and/or may be the result of more people living near grasslands and starting fires accidentally.
“We expect to see more rapid fires in the future,” Balch said.
“Destructive and fast-moving wildfires like the Campfire in California and the Lahaina fire in Hawaii show how important it is to plan for them.”
Reference
Balch, JK, Iglesias, V., Mahood, AL, Cook, MC, Amaral, C., DeCastro, A., Leyk, S., McIntosh, TL, Nagy, RC, St Denis, L., Tuff, T. , Verleye, E., Williams, A.P., & Kolden, C.A. (2024). Fastest growing and most destructive wildfires in the US (2001 to 2020). Science, 386(6720), 425–431. https://doi.org/10.1126/science.adk5737
