The disturbed terrain adjacent to the airstrip at Sachs Harbour is an example of man-induced thermokarst processes operating within the High Arctic environment. An irregular topography of mounds and linear depressions has appeared and evidence indicates preferential subsidence along ice wedges. The underlying sands and gravels are ice-rich with approximately 20–35% excess ice and natural water (ice) contents of between 50 and 150%. Examination of air photographs indicates that the terrain developed within three years of the initial disturbances. Detailed levelling in 1972 and 1973 suggests that subsidence and permafrost degradation is still active, over 10 years later. Gullying of the airstrip is a problem partly associated with the thermokarst activity. A comparison is made with man-induced thermokarst terrain in Siberia.