The construction of ski runs with artificial snowmaking in mountain areas changes natural water circulation and leads to activation of erosion and accumulation processes. To recognise this relationship, we selected a small catchment in the Gubałowskie Foothills, the Inner Carpathians, where 17% of the area is covered by the ski runs. The main purpose of our study was to: (i) present morphology and morphometrics of channels that drain and do not drain ski runs; (ii) recognise differences in statistical relationships between channel morphometrics in both types of channels; and (iii) estimate morphometric changes due to erosion and accumulation processes in selected channels. To identify these changes, we conducted geomorphological mapping of step pool channels, statistical analyses, DEM (Digital Elevation Model), and DOD (DEM of Difference) analyses (based on point clouds from 2016 and 2023). In order to identify the effect of ski run construction on channel morphology, we divided channels into two groups: 1) stream channels that do not drain ski runs, and 2) stream channels that drain ski runs. Results showed that the routing of drainage from the ski runs to the channels leads to a significant intensification of erosion in the channels with the maximum deepening, up to 2.6 m. It also changes the dominant geomorphological processes in the channels. Fluvial processes are beginning to dominate slope processes. The described changes occurred already 8 years after the opening of the ski station and reveal the scale of land degradation connected to artificial snowmaking in ski resorts.