The empirical formulations to forecast landslide generated water waves, recently defined in the framework of a research program funded by the Italian National Dam Office RID (Registro Italiano Dighe), are here used to study three real cases of subaerial landslides which fell down italian artificial reservoirs. It is well known that impulse water waves generated by landslides constitute a very dangerous menace for human communities living in the shoreline of the artificial basin or downstream the dam. In 1963, the menace became tragedy, when a 270 millions m³ landslide fell down the Vajont reservoir (Italy), generated an impulse wave which destroyed the city of Longarone, and killed 2000 people. The paper is aimed at presenting the very satisfactorily reproduction of the events at hand by using forecasting formulations.

The accurate modeling of the landslide‐generated tsunami characteristics in the so‐called near‐field is crucial for many practical applications. In this paper, we present a new full‐3‐D numerical method for modeling tsunamis generated by rigid and impermeable landslides in OpenFOAM® based on the overset mesh technique. The approach has been successfully validated through the numerical reproduction of past experiments for landslide‐generated tsunamis triggered by a rigid and impermeable wedge at a sloping coast. The method has been applied to perform a detailed numerical study of the near‐field wave features induced by submerged landslides. A parametric analysis has been carried out to explore the importance of the landslide's initial acceleration, directly related to the landslide‐triggering mechanisms, on the tsunami generation process and on the related wave properties. Near‐field analysis of the numerical results confirms that the influence of the initial acceleration on the tsunami wave properties is significant, affecting wave height, wave period, and wave celerity. Furthermore, it is found that the tsunami generation mechanism experiences a saturation effect for increasing landslide's initial acceleration, confirming and extending previous studies. Moreover, the resulting extended database, composed of previous experimental data and new numerical ones, spanning a wider range of governing parameters, has been represented in the form of a “nondimensional wavemaker curve,” and a new relationship for predicting the wave properties in the near‐field as a function of the Hammack number is proposed.