Mundakkai-Chooralmala landslide: assessment of initiation, progression, and impact

Abstract

Abstract Globally, the emergence of multi-hazard scenarios and cascaded disasters is significantly rising . During the 2024 monsoon in Wayanad District, Kerala, India, torrential rainfall triggered landslides, erosion, and flash floods, resulting in over 400 deaths. This prompted a study on (a) landslide initiation, (b) progression, (c) impact zones, and (d) disaster risk reduction strategies. A multidimensional landslide assessment framework was adopted encompassing hydrometeorology, geology, geotechnical, geomorphology, and damage assessment. Expert consultations and literature review were employed for parameter selection, followed by (a) field investigation and stakeholder interactions, (b) data acquisition via remote sensing, gauge stations, and laboratory tests, (c) data processing and analysis through correlation studies, geotectonic mapping, hydro-meteorological and slope stability modeling, and morphometric analysis, (d) validation using field observations, statistical and modelling outputs, and (e) formulation of recommendations. Findings indicate 280% rainfall increase on July 29th, and extensive 15-day antecedent rain causing oversaturation and triggering the event. Geomorphometric analysis shows regional lineaments influenced by a high bifurcation ratio and drainage density, accelerated debris flow into a channel-confined flash flood. Over 200 buildings were impacted along a six km runout path. This study recommends higher rain gauge density, pore pressure monitoring, and a multi-hazard approach to strengthen early warning and preparedness in the Wayanad region.

Keywords

• Landslide
• Slope instability
• Early warning system
• Integrated platform
• Disaster resilience
• Rainfall thresholds