Atmospheric rivers catalyze snowmelt and contribute to chains of landslides

Abstract

Atmospheric rivers (ARs) significantly impact hydrometeorological conditions by transporting large amounts of heat and water vapor, often resulting in extreme weather events and geohazards such as landslides. While the role of ARs in producing extreme rainfall and related landslides is well established, their influence on landslides through temperature-driven snowmelt remains poorly understood. Here, we examine this mechanism using 330 recorded landslides from February to April 2022 across the North Anatolian Mountains (T & uuml;rkiye). Our results demonstrate that ARs significantly contributed to snowmelt (up to 250 mm per event), stimulated by abrupt temperature increases (up to +6 degrees C) and rain-on-snow conditions, with rainfall and snowfall reaching up to 100 mm and 40 mm, respectively; all differences were statistically significant (p < 0.01) when comparing AR and non-AR days. These processes shifted landslide activity to higher elevations and steeper slopes over time, with median values rising from 330 m to 549 m and 16 degrees to 21 degrees, respectively. The results highlight the compound effect of ARs on landslide initiation and suggest that warming-driven snowmelt can substantially contribute to slope destabilization. This study provides a framework for understanding AR-related landslide hazards in other midlatitude mountain regions, including the Pacific Rim, the Andes, High Mountain Asia, and the Alps. As climate change is projected to amplify the frequency, intensity, and spatial extent of ARs, the risk of AR-induced geohazards is therefore likely to intensify further in such mountainous regions.