Record monsoon floods and landslides have killed more than 600 people across Sri Lanka, Indonesia, Thailand and Malaysia, with Sri Lanka’s central highlands and Indonesia’s West Sumatra and South Sulawesi provinces suffering major slope failures. Prolonged rainfall well above seasonal averages has triggered debris flows, embankment breaches and riverbank collapses, overwhelming drainage canals and older flood defences in low-lying urban areas. Geotechnical teams are prioritising emergency slope stabilisation, rapid debris clearance on key highways and reassessment of design rainfall and factor-of-safety assumptions for cut slopes and retaining structures.

A catastrophic landslide in Afaahiti on Tahiti’s southeastern coast has killed at least eight people and left several missing after heavily saturated hillside slopes collapsed during intense rainfall. The failure involved a steep, previously vegetated slope above residential areas, with debris flows destroying multiple homes and blocking local roads that connect to the coastal ring route. Authorities are now assessing residual slope stability, potential for secondary failures, and the need for rapid drainage works, slope reinforcement and revised setback distances for hillside development.

Torrential monsoon rainfall over the past week in North Sumatra has triggered debris-laden flash floods and multiple landslides, killing at least 10 people and leaving six missing in districts including Toba and Samosir. Police and BNPB teams report riverbank failures and slope collapses along road corridors and near settlements, with access to several upland villages cut by washed-out embankments and blocked mountain passes. For geotechnical and civil engineers, the events point to highly saturated residual soils, inadequate slope drainage, and vulnerable transport links in steep catchments during peak monsoon conditions.