Wildland-urban interface expansion increases U.S. wildfire risks

Wildfires in the United States are increasingly impacting the wildland-urban interface (WUI), the zone where human development meets undeveloped land. This area is the fastest-growing land-use type in the country, with over 44 million homes located in the WUI as of 2020, representing one-third of the national population.

In Reno, Nevada, rapid population growth has pushed new developments into fire-prone scrublands near the Sierra Nevada foothills. The recent Hawk fire, which ignited near a residential neighborhood, forced the evacuation of more than 40,000 people, highlighting the risks of sprawling development in these zones.

Experts note that wildfire seasons are lengthening due to extreme heat and dry conditions. Furthermore, human activity was responsible for an average of 89% of wildfires between 2018 and 2022. In WUI environments, fires are fueled not only by natural vegetation but also by synthetic materials found in homes, vehicles, and office buildings, making them more difficult to control.