Catastrophic landslides are often preceded by a stage of creeping behavior during a certain time. The paper focusses on the transitional behavior from slow creeping motions to rapid events by evoking two phenomena: the strain rate effects on friction (which explain the creeping motion) and the thermo-mechanical interaction at the scale of the sliding surface and its vicinity. A coupled formulation for the relevant physical phenomena is presented. It was formulated in dimensionless terms with the purpose of generalizing the results beyond specific cases. A few dimensionless parameters were found to control the entire deformation process. A sensitivity analysis provides considerable insight into the evolution of the sliding velocity and its eventual blow-up. The blow-up takes place when thermal pressurization dominates the slide motion. It may occur for a combination of different factors mainly related to specific properties of the shear band. It depends also on the current straining rate of the landslide which is a consequence of the unbalanced forces. The formulation developed is applied to planar slides. The effect of the kinematics of the landslide and of relevant parameters is discussed in terms of the evolution of the motion.