Slope failures can happen on gentle slopes, not just steep ones, due to water flowing upwards in the soil. Researchers studied slope failures on a gradual slope in Korea from 2004 to 2017. They used artificial rainfall in experiments to show how water moving upwards can cause slope failures. The soil becomes saturated and has high water pressure, leading to the slope collapsing. This upward water flow is a key factor in causing slope failures on gentle slopes in granite areas.