The Western Ghats is one of the most landslide-prone areas of Kerala. This study focuses on conducting a Slope Stability Analysis in the Idukki district of Kerala, India, utilizing the GIS-TISSA (GIS Tool for Infinite Slope Stability Analysis) methodology. The approach involves the integration of a root cohesion estimation equation and geoprocessing tools of ArcGIS to evaluate the factor of safety value in a specified area. Inputs utilized in the slope stability analysis include a Digital Elevation Model (DEM), soil map, and tree root strength. The study also incorporates the 5-day antecedent rainfall threshold equation for the region, which enables the identification of critical rainfall conditions that may trigger landslides in unstable areas. The primary objective of this research is to develop a warning system for landslides in the region, whereby exceeding critical rainfall conditions could potentially result in landslides. This system aims to minimize the adverse impacts of landslides on the local population and infrastructure.