In engineering applications snow is often loaded by a rapid impact of high stress. As a result, it suddenly transforms from a porous sintered solid into a granular medium. In order to capture the fundamental mechanical behavior of snow in rapid impact loading a discrete element (DE) model is the most physically appropriate. It explicitly includes all the relevant components: the snow microstructure, the rearrangement of the grains and the bonding between them. We developed, calibrated and tested a DE snow model that can predict the mechanical response of the snow in rapid loading. In this model, snow grains are represented by randomly distributed elastic spheres connected by elastic-brittle bonds. Model parameters include density, grain size and bond strength. The model was calibrated by several different high strain rate laboratory mechanical tests performed on a custom built machine. We demonstrate the performance of the DE snow model by the simulation of Al blocks sliding on snow. The model successfully reproduces the fundamental characteristics of the block friction mechanisms and accounts for the difference in friction due to the block geometry.