Minkowski densities and density functions are measures for quantifying arbitrary binary patterns. They are employed here to describe permafrost patterns obtained from aerial photographs. We demonstrate that images taken at two neighbouring sites shown distinctly different patterns and quantify the difference. It is found that one of the sites exhibits an essentially single-scale structure while the other one has a multiscale organization. Minkowski densities and density functions are thus proposed as sensitive and objective measures to quantify the change of permafrost patterns in space or in time. Copyright © 2005 John Wiley & Sons, Ltd.