It is well known that grain boundary processes - intercrystalline sliding and grain boundary migration - make an important contribution to high temperature deformation of polycrystalline materials, particularly for metals. More recently, these processes have been correlated with the atomic structure of the boundaries. Our goal is to study sliding and migration of ice boundaries, with respect to temperature, stress, and the crystallographic parameters which characterize the boundaries. We here present our fiirst results, obtained on bicrystals with high angle boundaries.