To improve the understanding on the frontal behavior of submarine slides numerical simulations were performed to back-calculate laboratory experiments carried out at the St. Anthony Falls Laboratory, University of Minnesota. The slide and the ambient water are modeled by a two-phase model approach, which allows the study of the interaction between the slide and the ambient water. The presented simulations focus on clay-rich materials. They show the development of a high-pressure wedge of ambient water underneath the slide and of underpressure along its upper surface, which, in agreement with the laboratory experiments, leads to a hydroplaning head. In addition, a velocity decrease from the head to the tail of the slide could be observed, which leads to stretching of the slide mass. Stretching and thinning of the slide contributes to the softening of the material and may lead to progressive detachment of the head and development of out-runner blocks.