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Prescribed fire, managed burning, and previous wildfires reduce the severity of a southwestern US gigafire

Year of Publication
2025
Publication Type

In many parts of the western United States, wildfires are becoming larger and more severe, threatening the persistence of forest ecosystems. Understanding the ways in which management activities such as prescribed fire and managed wildfire can mitigate fire severity is essential for developing effective forest conservation strategies.

Increasing Hydroclimatic Whiplash Can Amplify Wildfire Risk in a Warming Climate

Year of Publication
2025
Publication Type

On January 7 and 8, 2025, a series of wind-driven wildfires occurred in Los Angeles County in Southern California. Two of these fires ignited in dense woody chaparral shrubland and immediately burned into adjacent populated areas–the Palisades Fire on the coastal slopes of the Santa Monica Mountains and the Eaton fire in the foothills of the San Gabriel Mountains.

Compounding effects of climate change and WUI expansion quadruple the likelihood of extreme-impact wildfires in California

Year of Publication
2025
Publication Type

Previous research has examined individual factors contributing to wildfire risk, but the compounding effects of these factors remain underexplored. Here, we introduce the “Integrated Human-centric Wildfire Risk Index (IHWRI)” to quantify the compounding effects of fire-weather intensification and anthropogenic factors—including ignitions and human settlement into wildland—on wildfire risk.

Spatial and temporal trends in causes of human-ignited wildfires

Year of Publication
2025
Product Type
Date Published

Red flag warnings (RFWs) are issued to alert management and emergency response agencies of weather conditions that are conducive to extreme wildfire behavior. Issuance of RFWs also can encourage the public to exercise extreme caution with activities that could ignite a wildfire. Among the ignition causes associated with human activity, some generally reflect short-term behavioral decisions, whereas others are linked to infrastructure and habitual behaviors. From 2006–2020, approximately 8% of wildfires across the western United States were discovered on days with RFWs. We discuss our discovery that although the number of human-caused fires was higher on RFW days than on similar days without RFWs, the warnings appeared to disproportionately reduce the number of ignitions associated with short-term behavioral choices.

Presenter: John Abatzoglou, University of California, Merced