We describe measurements of the growth rates of the basal and prism facets of ice crystals grown from the vapor phase at temperatures -39degreesC < T < - 10degreesC. We find that all our data can be well described by a model in which the facet growth is limited primarily by 2D nucleation over this temperature range. The inferred critical supersaturations, and thus the step edge free energies, are essentially identical for the two facets, with values that decrease monotonically with increasing temperature. The growth scaling parameters, on the other hand, exhibit a more complex behavior with temperature that is quite different for the two facets. These data suggest that much of the peculiar behavior seen in ice crystal growth from vapor is due to differences in the surface diffusion of admolecules on the two principal facets. (C) 2002 Elsevier Science B.V. All rights reserved.