On the morning of July 30, 2024, a catastrophic landslide struck Wayanad, India, in the ecologically sensitive Western Ghats, claiming over 260 lives, with many still missing beneath the debris. Here, we present a comprehensive overview of the landslide event based on field, satellite, and aerial images analysis, numerical modeling, and geotechnical testing to unravel the failure mechanism and its catastrophic impact on downstream communities. Our analysis revealed that a pre-existing crack, formed in 2020, acted as the initiation point for the recent failure. The underlying weathered and sheared geology, coupled with structural discontinuities, and thick soil strata, exacerbated by intense rainfall on July 29-30, catalyzed the transition of a planar slide into a catastrophic debris flow. Numerical simulations indicate that the debris flow initiated around 01:00 h, peaked at 04:00 h, and reached a maximum velocity of 28 m/s. The estimated volume of displaced material ranged between 5.17 x 106 and 5.72 x 106 m3, ranking it among the largest debris flows in India. The flow's run-up height in the transitional zone reached 32 m, amplified by multiple damming effects and topographic features such as cascades and river sinuosity, causing extensive infrastructure damage to the downstream population. Given the terrain's known fragility and history of sequential events, this region requires urgent attention for real-time monitoring and mitigation strategies to reduce future risks.

Most of the sections of the Western Ghats ( in Kerala) are highly susceptible to landslides, particularly during extreme rainfall events (EREs). The massive landslide that occurred in the Mundakkai-Chooralmala region of Wayanad district on 30 July 2024 is the latest in a series of devastating landslides in this region. This event caused extensive damage, resulting in over 225 fatalities, more than 273 injuries, about 131 individuals reported missing, and the destruction of 1555 houses, making it one of the deadliest landslides in India. This investigation synthesizes the formation mechanisms, landslide characteristics and impacts of the event through the analysis of field observations, aerial photographs, satellite imageries and rainfall data. Results indicate that the region has been prone to landslides including those events in 1924, 1984, and the recent ones since 2018. The Mundakkai-Chooralmala landslide is the largest landslide that occurred in the Kerala, with an impact area of approximately 6.5 x 10(5) m(2) and a horizontal runout distance of similar to 7 km. Rainfall analysis shows that the landslide-affected region received extreme rainfall amounting to 373 mm within 24 h of the event. The antecedent rainfall for three days and five days was 586 mm and 809 mm, respectively. This extreme rainfall, combined with highly weathered and sheared geological conditions and unique slope morphological characteristics, triggered the landslide. The affected areas are characterized by loose, unconsolidated sediments, including a thick layer of weathered, soft lateritic soil (exceeding 30 m in thickness) and micaceous kaolinitic plastic clay, resting on highly weathered and jointed bedrock, such as charnockites and gneisses. These conditions, combined with prolonged and intense rainfall, increase pore water pressure, significantly reducing overburden shear strength. The concave slopes of the terrain further exacerbate this risk by accumulating surface runoff, making these slopes more susceptible to future failures. Field evidence also indicates the formation of debris dams in narrow sections of the valley due to dislodged material, including trees and large boulders. The breaching of these natural dams caused widespread damage throughout the affected areas. These findings underscore the urgent need for comprehensive landslide risk management strategies, including the implementation of early warning systems, improved land use planning, and community preparedness to mitigate the impact of future landslides in the Western Ghats region.