This chapter presents Material Point Method simulations of granular column collapses and demonstrates the influence of some numerical features, including the the constitutive model, on the failure mechanism and run-out distance. The granular column collapse is a good example of a well-established experiment, which permits exploring the failure of granular materials, its post-failure fluid-like behaviour, and its deposition mechanism. The experimental layout can be axisymmetric or plane strain. This model is used to carry out parametric analyses illustrating the influence of the different modelling choices on the collapse behaviour and run-out distance. All materials require a constitutive model to convert the strains into stresses and to give the material a certain stiffness. The stresses are initialised at the beginning of the simulations by gravity loading and during which the system is damped in order to avoid straining the soil. The comparison of the results illustrates the mesh dependency for the failure surface, although the run-out distances are similar.