###### Abstract  
The stability analysis of rainfall-induced slope failures considers a number of factors including the characteristics of the rainfall, vegetation, geometry of the slope, unsaturated soil characteristics, infiltration capacity, and saturation degree variations. Amongst all these factors, this study aims to investigate the effects of the antecedent rainfall and saturation conditions. A numerical modeling study was conducted using finite difference code software on a representative slope geometry with two different soil types. Two scenarios were followed: The first involved the application of three different rainfall intensities for varying initial saturation levels between 40% and 60%, representing the antecedent saturation conditions. The second scenario involved modeling successive rainfalls for a typical initial saturation degree of 50%. The impact of antecedent rainfall was assessed by determining the time required for failure during the application of a main extreme rainfall after a preceding rainfall of varying durations. Consequently, a zone of susceptible time for failure was suggested for use as a criterion in hazard management, allowing for the tracking of rainfall and its duration through the proposed chart for potential failures. Once the anticipated critical rainfall intensities have been determined through a meteorological analysis, a risk assessment for a specific slope can be conducted using the proposed practical procedure. Accordingly, a control mechanism may be established to detect the potential for a natural hazard. Furthermore, the proposed procedure was applied to a case study, whose modeling insights were in harmony with the real conditions of the slope failure. Thus, this demonstrated the significance of the antecedent conditions in modeling landslides triggered by rainfalls. slope failure; rainfall; unsaturated soils; natural hazards; climate change; landslides +
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due to the fact that the soil characteristics were not simply dependent on the bedrock type. On the other hand, conventional approaches on slope stability suggested the evaluation of classical soil mechanics assumptions; yet, the problem with natural slopes is that slopes may lose their stability after being subjected to rainfall due to the increase in their saturation, resulting in a decrease in their suction stresses [6; 7; 8; 9; 10; 11; 12]. [PERSON] and [PERSON] [13] investigated the parameters affecting the stability of the unsaturated soil slope subjected to rainfall. Low-intensity rainfalls with longer durations were found to be as destructive as high-intensity rainfalls with shorter durations. For soils with an intermediate permeability (10\({}^{-4}\)-10\({}^{-7}\) m/s), the infiltration and drainage equilibrium were found to be very effective on the change in pore pressure. On the other hand, [PERSON] et al. [14] stated that the slope stability of low-conductivity soils was affected more significantly than high-conductivity soils when subjected to three antecedent rainfall patterns in their study. Similarly, the initial degree of saturation or antecedent water content values was found to have a significant influence on the behavior of clayey soils when compared to that of silty soil [15]. Careful attention is needed when evaluating the stability of a slope for it is possible for it to end up being a geotechnical hazard. In January 2021, a huge rainfall-triggered landslide occurred after four hours of rainfall and finally caused the death of 32 people and much social and economic damage [11]. [PERSON] et al. [16] identified deadly landslides in 128 countries over 20 years and, in this duration, 3876 landslides were found to cause almost 164,000 deaths. The study also confirmed that the events mostly took place where a risk of extreme rainfall conditions were defined. The situation also gains importance from climate change resulting in unexpected rainfall series.