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Large wildfire-driven increases in nighttime fire activity observed across the conterminous United States

Date: December 07, 2021

Satellite sensors are detecting increasing trends in nighttime wildfire activity.


Maps of fire activity partitioned into into whether active fire pixels were detected during the daytime or nighttime and whether they were detected outside or inside wildfires. 94% of nighttime fire activity occurred within wildfires.
Fire radiative power (FRP) detected by MODIS partitioned into whether active fire pixels were detected during the daytime or nighttime and whether they were detected outside or inside wildfires.

Nighttime wildfire fire activity exposes firefighters to the risks of working in the dark and limits their opportunities for rest and recovery. Under rare conditions, extreme nighttime fire behavior can threaten communities. Therefore, understanding the potential for a wildfire to continue burning through the night has important implications for firefighter and community preparedness. Nevertheless, little attention has been paid to the spatiotemporal patterns of nighttime wildfire activity across the conterminous United States.  

This study used nearly two decades (2003–2020) of satellite observations from the Moderate Resolution Imaging Spectroradiometer (MODIS) to characterize the diurnal dynamics of vegetation fires across the conterminous U.S. These satellite observations were stratified according to vegetation fire type, wildfire size, and time of detection (day/night).

Whereas daytime fire activity was widespread both outside and inside wildfires, nighttime fire activity was concentrated inside wildfires, and particularly within large wildfires in the western U.S. Analysis of coincident 1000-hr fuel moistures indicated that as fuels dried out, MODIS detected less agricultural and prescribed fire activity and increasingly larger and more intense wildfires with higher probabilities of nighttime persistence. Over the past 18 years, coincident with an increase in wildfire sizes, MODIS has detected significant increasing trends in nighttime wildfire activity.

Key Findings

  • A graph of nighttime fire activity from 2003-2020 showing a significant increase over time.
    Since 2003, MODIS has detected a significant increasing trend in nighttime wildfire activity.
    The majority of nighttime fire activity detected by satellites from 2003-2020 was emitted from large wildfires burning during drier conditions.
  • Observed increases in nighttime fire activity since 2003 have coincided with increasing wildfire sizes.

 

Featured Publications

Freeborn, Patrick ; Jolly, William M. ; Cochrane, Mark A. ; Roberts, Gareth , 2022
Jolly, William M. ; Cochrane, Mark A. ; Freeborn, Patrick ; Holden, Zachary A. ; Brown, Timothy J. ; Williamson, Grant J. ; Bowman, David M. J. S. , 2015


National Strategic Program Areas: 
Wildland Fire and Fuels
National Priority Research Areas: 
Climate Change; Forest Disturbances
RMRS Science Program Areas: 
Fire, Fuel and Smoke
RMRS Strategic Priorities: 
Fire Sciences
Geography: 
National
Principal Investigators: 
Principal Investigators - External: 
Mark A. Cochrane - University of Maryland Center for Environmental Science
Gareth Roberts - University of Southampton