Retrogressive thaw slumps are very large landslide-like features occurring in the presence of massive ground ice. This form of thermokarst is generally initiated by lake shore erosion, coastal erosion or nearshore thaw settlement leading to the failure of coastal cliffs and the (re)exposition of ice-rich permafrost. These slumps can then evolve over hundreds of years and deliver large quantities of sediments and nutrients to the nearshore zone. In this presentation, we show examples from the Yukon Coastal Plain in Canada, where retrogressive thaw slumps are among the largest in the world. We introduce the notion of polycyclic occurrence of these slumps as well as the coupling of this polycyclicity to climatic signals. We also show field and remote sensing data describing the large quantities of sediment and nutrient released by these features and provide a comparative analysis of the impact of coastal thermokarst and erosion of coastal cliffs.