###### Abstract  
The Ludoialm landslide, which is located in the municipality of Munster in Tyrol, Austria, represents a large-scale translational landslide in glacial soil sediments characterised by an exceptionally low inclined basal shear zone of only 12\({}^{\circ}\). Although a temporal coincidence between meteorological events and slope displacement is obvious, the hydromechanical coupled processes responsible for the initial landslide formation and the ongoing movement characteristics have not yet been identified. This article provides a comprehensive analysis of the predisposition factors and the initial failure mechanism of this landslide from geological and geotechnical perspectives. We use a prefailure geometry of the cross section to simulate the initial slope failure process by a limit equilibrium analysis (LEA), a strength-reduction finite element method (SRFEM), and a finite element limit analysis (FELA). The shape and location of the computationally obtained basal sliding zone compare well with the geologically assumed one. Based on the computational study, it turns out that a high groundwater table probably caused by snow melting in combination with different permeabilities for the different layers is needed for the formation of the exceptionally low inclined basal shear zone. This paper presents the failure mechanism of the Ludoialm landslide and discusses the role of the shear band propagation in the process of slope destabilization. slope stability; trigger factor; snow melting; seepage; permeability; geotechnical computation (2023) 2023 2 instability due to snowmelt is therefore not a rare phenomenon in the world [14; 15; 16; 17; 18; 19]. Rainfall or snowmelt events usually increase the pore water pressure in the slope [20; 21; 22; 23], and the effective normal stress is subsequently reduced [24; 25]. Compared to the usual short duration of rain infiltration, a more continuous supply of water can be provided by the snow-melting process over a longer period [26]. Numerous studies use remote sensing and geographic information systems (GIS) to understand the actual landslide conditions. Field surveys, i.e., geological-hydrogenical mapping, of landslide events and of their historical development process often employ remote sensing methods to derive digital elevation models (DEM), which provide the topography and also help to estimate the landslide geometry, the geological structure of the subsurface, and the volume of the material loss during the events. GIS have widely been used to map and predict landslide hazards and risks in past decades [5; 27; 28]. The topographical model derived by a field investigation is the basis of the geotechnical model used in the computation. Computational models, which focus on simplified slope geometry and geomechanical processes, can help to understand the slope failure mechanisms. The calculation results can explore some specific aspects of landslide events, e.g., slope deformations, initial failure processes, the volume of the material loss at failure, etc. [29]. The limit equilibrium analysis (LEA) [30; 31] is a conventional method for computing the stability of slopes. The advantages of this method are evident, e.g., it is simple and widely applicable. The finite element method [32; 33] based on the shear strength reduction concept (SRFEM) [34; 35; 36] and finite element limit analysis (FELA) [37] are two state-of-the-art numerical techniques for slope stability analysis [38; 39]. In recent years, SRFEM and FELA have been widely used [40; 41; 42; 43; 44; 45] to analyse landslides in mountain regions due to changing water tables (e.g., snowmelt, precipitation). In this work, we focus on the impact of water infiltration due to snowmelt on a slope with a particular hydrogeological situation characterised by two different layers resulting in a large permeability contrast. Few studies have been carried out on the influence of the different permeabilities of soil layers on slope stability [46].