New research has revealed that wildfires can leave behind persistent ‘heat islands’ that reshape weather patterns long after the flames are extinguished.
The study – titled Land–Atmosphere Interaction Responses of Burn Scar Heat Islands: A Case Study of the 2018 Camp Fire and published in the Bulletin of the American Meteorological Society (AMS) – was led by Andrew Blackford, a University of Alabama in Huntsville (UAH) Earth System Science Center (ESSC) researcher affiliated with NASA’s Marshall Space Flight Center.
UAH said the research provides one of the most comprehensive insights to date into how wildfire burn scars alter interactions between the land surface and the atmosphere.
Using the devastating 2018 Camp Fire in California as a case study, the research combines satellite observations with advanced numerical weather modeling to show that burned landscapes can become significantly hotter and drier than surrounding areas – forming what scientists describe as “burn scar heat islands”.
“These effects are similar in concept to urban heat islands, but they’re driven by wildfire-induced changes to the land surface,” said Blackford.
Wildfires strip away vegetation, darken soils and reduce the land’s ability to retain moisture. The study found that these changes dramatically alter how energy moves between the Earth and the atmosphere.
Despite a decrease in overall surface radiation, the researchers observed an increase in sensible heat – the direct transfer of heat from the Earth into the air. This leads to warmer surface air temperatures and lower humidity over burned areas.
The study revealed that burn scars can have consequences that extend beyond temperature alone. These areas can increase near-surface air temperatures while simultaneously decreasing dewpoint, leading to drier atmospheric conditions. Burn scars can also strengthen localized wind circulations and play a role in influencing cloud formation and even broader rainfall patterns.
“These changes can persist well after the wildfire event, especially in regions with complex terrain,” Blackford explained. “They have important implications for post-fire recovery, hazard mitigation and weather forecasting.”
Blackman said it was the first study to examine a burn scar’s effects on regional diurnal circulations, and it is also the first time “burn scar heat island” has been coined.
As wildfire frequency and intensity increase across the USA, understanding their long-term atmospheric impacts is becoming increasingly important. The findings suggest that post-fire landscapes should be considered in weather models, emergency planning and recovery strategies.
“This study shows that wildfire impacts extend beyond the immediate event,” said Dr Udaysankar Nair, a UAH professor of atmospheric and Earth science and co-author of the study. “They fundamentally change how the land and atmosphere interact.”
Looking ahead, Blackford said his work will continue to focus on extreme weather and land-atmosphere interactions.
“As we go forward and technology continues to advance, I expect our understanding of these microscale and mesoscale processes and responses to severe weather events altering land use and land cover to continue increasing. Ultra-finescale numerical modeling combined with observational analysis of these responses will be crucial to our understanding.”
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