We investigate the impact of land use changes and human activities in mountainous regions on landslide risks, with a specific focus on the sediment disasters induced by heavy rainstorms in South Korea in August 2022. Despite the occurrence of 481 sediment disasters in 2022, a figure not markedly higher than in past years, the notable concern is their concentration in densely populated urban areas. This pattern highlights the intensified risk of landslide damage due to urban expansion. Field investigations at two debris flow sites have revealed the complex relationship between urbanization, climate change, and the increasing risk of landslides. These findings point to an urgent need for future research into the dynamics of landslides, particularly how anthropogenic factors and altered rainfall patterns due to climate changes contribute to their frequency and magnitude. Such research must assess the impacts of deforestation and urbanization on landslide susceptibility, integrating the effects of climate change on rainfall patterns to develop effective mitigation strategies.