Quantifying the Effect of Precipitation on Landslide Hazard in Urbanized and Non‐Urbanized Areas.

Although most landslides are precipitation‐triggered, a number of other complex conditions simultaneously predispose any given slope to failure, with the impact of urbanization posing particular scientific challenges. We use panel regression with fixed effects—which controls for observed and unobserved time‐variant and time‐invariant influences—to quantify the effect of precipitation accumulation on landslide concentration across the Pacific Coast region of the United States. We find that landslide hazard is most sensitive to precipitation variations in urbanized areas. This finding is robust across 1‐day, 10‐day, and 30‐day periods of precipitation accumulation, among individual Pacific Coast states, and when the analysis is confined to the San Francisco Bay Area (a subregion with both urban and rural areas). Our results corroborate existing hypotheses that urbanization increases landslide hazard, while demonstrating the importance of considering interactions with urbanization when predicting landslide hazard in the current climate, and under climate change scenarios. Plain Language Summary: Generalizable understanding of where and how landslides occur may inform efforts to adapt to these devastating natural disasters. While most landslides are triggered by precipitation, a number of other complex factors also play a role in slope destabilization. Employing an empirical framework that accounts for these confounding factors, we find that landslide hazard is most sensitive to precipitation variations in urbanized areas. Our results enhance understanding of the impact of urbanization on precipitation‐triggered landslide hazard and highlight the importance of considering urbanization when predicting landslide hazard, particularly in response to global warming and climate change. Key Points: We quantify the effect of precipitation on landslide concentration within distinct land use types across the US Pacific CoastLandslide hazard is most sensitive to precipitation variations in urbanized areasResults highlight the importance of considering interactions with urbanization when predicting landslide response to climate [ABSTRACT FROM AUTHOR]