We propose a new type of crystal growth phenomenon-structure-dependent attachment kinetics-to explain the growth of thin ice plates from the vapor phase at temperatures near -15degreesC. In particular, we propose that the condensation coefficient for growth of ice prism facets increases dramatically when the width of the facet approaches atomic dimensions. This model reconciles several conflicting measurements of ice crystal growth and makes additional predictions for future growth experiments. Other faceted crystalline materials may exhibit similar morphological instabilities that promote the diffusion-limited growth of thin plate-like or needle-like crystal structures. (C) 2003 Elsevier B.V. All rights reserved.