Piping has been recognized as an important geomorphic, soil erosion and hydrologic process. It seems that it is far more widespread than it has often been supposed. However, our knowledge about piping dynamics and its quantification currently relies on a limited number of data for mainly loess-derived areas and marl badlands. Therefore, this research aimed to recognize piping dynamics in mid-altitude mountains under a temperate climate, where piping occurs in Cambisols, not previously considered as piping-prone soils. It has been expressed by the estimation of erosion rates due to piping and elongation of pipes in the Bereźnica Wyżna catchment in the Bieszczady Mountains, eastern Carpathians (305 ha, 188 collapsed pipes). The research was based on the monitoring of selected piping systems (1971–1974, 2013–2016). Changes in soil loss vary significantly between different years (up to 27.36 t ha−1 yr−1), as well as between the mean short-term erosion rate (up to 13.10 t ha−1 yr−1), and the long-term (45 years) mean of 1.34 t ha−1 yr−1. The elongation of pipes also differs, from no changes to 36 m during one year. The mean total soil loss is 48.8 t ha−1 in plots, whereas in the whole studied catchment it is 2.0 t ha−1. Hence, piping is both spatially and temporally dependent. The magnitude of piping in the study area is at least three orders of magnitude higher than surface erosion rates (i.e. sheet and rill erosion) under similar land use (grasslands), and it is comparable to the magnitude of surface soil erosion on arable lands. It means that piping constitutes a significant environmental problem and, wherever it occurs, it is an important, or even the main, sediment source. Copyright © 2017 John Wiley & Sons, Ltd.