Who dies in wildfires? Common denominators of fatal wildfires in the US

In the United States, catastrophic wildfires have killed hundreds of people in recent years, including two high fatality events in the 2018 Camp Fire in California and the 2023 Lahaina Fire in Hawaii. These disasters were astounding not only because so many died so quickly, but also because they represent a shift in understanding of who dies in contemporary wildfires. For much of the 20^th century, the primary lives lost in wildfires were the front line firefighters at the greatest risk. Over the last two decades, however, climate change has increased the extremity of wildfire behavior and resulted in numerous catastrophic wildfire events globally where dozens of civilians were killed. Here we evaluate both the biophysical drivers of fatal wildfires in the US and the social characteristics of wildfire fatalities. Downslope winds during drought conditions at the wildland-urban interface are the primary indicators of civilian fatalities, particularly in specific forest-shrubland interface Mediterranean fuel types and in complex terrain. Social vulnerability of the resident population was also a key driver of fatalities, as older populations with lower levels of mobility struggled to evacuate with no advanced notice. Fires that killed civilians stood in stark contrast to fires that killed firefighters, which occur primarily during peak fire season during extreme heat events and in rural, relatively forested areas. These differences highlight a critical gap in understanding how to mitigate civilian wildfire fatalities.