Rescal-snow is a model of dunes and snow waves. When wind blows over snow, it self-organizes. This forms surface features, such as ripples and dunes, that alter the reflectivity and thermal conductivity of the snow. Studying these features in the field is cold and challenging, so Rescal-snow was created to enable snow scientists to study snow features in controlled numerical experiments. This modelis intended for researchers in snow science, geomorphology, and polar climate.