Catastrophic landslides, which often occur abruptly after months or years of creep, threaten mountain safety. Hence, comprehensive prediction of catastrophic landslides is necessary for safety in mountainous areas. Such prediction requires a clear understanding of the creep-to-runout transition, which remains elusive. In this study, a two-wedge Vajont model that accounts for the effects of pore water pressure and friction strengthening and weakening is utilized to predict the behavior of catastrophic landslides. The friction strengthening and weakening controlling the creep-to-runout transition are determined based on the rotary shear experimental data of Vajont landslide materials. Friction strengthening-the phenomenon in which the friction coefficient increases with increasing velocity-always occurs in the creep velocity zone, reducing the creep velocity to zero. Consequently, the friction strengthening and effect of pore water pressure exhibit feedback simultaneously. However, if the pore water pressure effect increases sufficiently to counteract the friction strengthening effect, the velocity can surpass the upper limit of the creep, and friction weakening can occur. Friction weakening causes the friction coefficient to decrease with increasing velocity, resulting in landslides sliding faster and causing catastrophes. Furthermore, it is found that sufficient pore water pressure due to rainfall is a necessary trigger. This study is expected to provide new ideas for catastrophic prediction.