Review article: rainfall-induced landslide early warning systems through the lens of the early warnings for all framework – advances, gaps, and perspectives

This review is necessary to provide a comprehensive evaluation of rainfall-induced landslide early warning systems (LEWS) through the lens of the United Nations “Early Warnings for All” (EW4All) framework. This study integrates EW4All pillars, examines information sharing in academic publications and official websites/portals, and evaluates the global feasibility of implementing EW4All for LEWS. Of 45 rainfall-induced systems, 27 (26 LEWS and one forecasting-focused system) were found operational (benefiting 19 countries), meaning they were implemented and actively used for warning purposes when this paper was prepared. Some forecasting-focused systems were misleadingly described as early warning systems. Among Local, Regional and National systems, Local systems were often less scalable and more resource-intensive. Operational systems were mainly National, followed by Regional. Most operational systems relied on rainfall thresholds. Some included susceptibility maps; risk maps were largely absent. Real-time sensor data were used in some systems; however, high maintenance costs limited scalability. Reliability was further constrained by data scarcity, limited forecast verification, and suboptimal use of Artificial Intelligence. Community engagement was infrequently documented in the reviewed systems. Although EW4All is transformative, implementing effective LEWS across rainfall-induced landslide-prone areas worldwide by 2027 remains impractical without localised approaches, sufficient funding, community engagement, and enhanced institutional capacity.