In July 1996, Typhoon Herb swept across Taiwan, bringing torrential rainfall -the most intense of the century. The disaster resulted in 73 casualties and served as a harsh lesson on the destructive power of debris flows, which wiped out entire villages and properties. Debris flows directly struck villages at the foothills of slopes vulnerable to rainfall-induced failures, including the houses shown in Fig. 1. Debris flows begin when debris is abruptly discharged into gullies following shallow slope failures. The debris forms a high-density, mud-like flow that washes away infrastructure, including bridges, retaining walls, and embankments, as illustrated in Figs. 2 and 3.

　　Potential shallow failures of slopes can be predicted when geological and geo-environmental factors are correctly integrated with a slope stability analysis tool such as SLOPE-ffdm 2.0. Failures in soil-retaining walls, which are crucial to highway embankment stabilization, can be prevented by employing advanced techniques such as soil reinforcement and soil nailing. SLOPE-ffdm 2.0 is a powerful tool that enables engineers and researchers to ensure slope and retaining wall stability under abnormal loading or environmental conditions.