Study quantifies ‘hot drought’ impact: 2025 Los Angeles wildfire risk amplified by up to 210%

As the one-year anniversary of the devastating early January 2025 wildfires in Los Angeles approaches, a pressing question remains: what made these fires, among the most destructive in the region's history, so extreme? New research now provides a quantifiable answer, pinpointing the critical role of combined high temperatures and drought conditions.

Global climate change is intensifying extreme weather events like heatwaves and droughts, which in turn are altering the frequency, intensity, and spatial patterns of wildfires worldwide. In early January 2025, catastrophic wildfires erupted in the Los Angeles region, causing severe societal and environmental impacts. The mechanisms behind their unprecedented ferocity, particularly the contribution of meteorological conditions, have been unclear.

To address this, an international team of scientists from the Institute of Atmospheric Physics at the Chinese Academy of Sciences, Nanjing University of Information Science and Technology, and the University of Wisconsin-Madison investigated the fires’ characteristics. They used a Copula-based Bayesian probability framework to quantify how "hot drought" conditions influenced the likelihood of such an event.

Their study, published in Advances in Atmospheric Sciences, reveals that the 2025 Los Angeles wildfires represent a roughly once-in-67-year event for the region's typical rainy season. The fires were primarily driven by compound hot and dry conditions. The analysis shows that the extreme drought during the fire period increased the probability of wildfires with similar intensity and burned area by 54% and 75%, respectively. When compounded by high temperatures, these probabilities were dramatically amplified further—by 149% for intensity and 210% for burned area.

Beyond hot drought, other factors converged to fuel the disaster. Above-average precipitation in the late winters of 2023 and 2024 promoted abundant vegetation growth. This was followed by an extended period of hot, dry conditions that desiccated this vegetation, creating ample fuel. Additionally, strong, dry Santa Ana winds played a significant role in fire spread. Compared to weak wind conditions, strong winds increased the probability of such severe fires under hot-drought scenarios by 119% for intensity and 387% for burned area.

"Our findings indicate a sharply increasing risk of large, intense wildfires under hot drought conditions, even outside the traditional fire season," said lead author Dr. Feng Ma. "This highlights an urgent need for enhanced attention and adaptive response strategies for year-round wildfire risk in a changing climate."

The research underscores how climate change and variability is creating novel and dangerous fire weather scenarios, extending risk into seasons historically considered less vulnerable.

The research team includes: Feng Ma from Nanjing University of Information Science and Technology; Xing Yuan from the Institute of Atmospheric Physics, Chinese Academy of Sciences; and Jason A. Otkin from the University of Wisconsin-Madison.

The study is part of an ongoing special collection on the 2025 LA wildfires organized by Advances in Atmospheric Sciences .  The collection is dedicated to advancing the science of wildfire diagnosis, early warning, and climate services, and is actively inviting further submissions.