Hydrological instability and archaeological impact in Northwest Greenland: Sudden mass movement events signal new concerns for circumpolar archaeology.

In the High Arctic, recent acceleration of geomorphological processes is having extreme impact on archaeological landscapes. In this paper, we consider implication for circumpolar archaeology, and focus analysis on a study area of critical importance to the local Inughuit community at Siorapaluk – a small settlement in Northwest Greenland. Using a combination of ground survey, historical satellite images, and Geographic Information Systems (GIS), we analyze damage zones to understand the character, timing, and extent of destruction. Three types of geomorphological processes are identified as causing significant damage, including: 1) debris flows, 2) active-layer detachment slides, and 3) alluvial deposition. These processes, we demonstrate, were amplified by extraordinary rainfall events that took place in the summers of 2016 and 2017 against a backdrop of broader climate change induced shifts in arctic precipitation. Further instability in the amount and seasonality of precipitation can be expected, and archaeological consequences will expand to areas that have so far been unaffected. The scale of mass movement that we document may be unprecedented in terms of the landscape's post-glacial development, and likely represents the onset of a new state in erosional maturity. We use our results to suggest criteria that can help predict and identify areas most at risk, which will be a critical component of prioritizing response measures. The suddenness through which mass movement went from background threat to primary destructive process makes the case of Siorapaluk relevant to archaeologists working in periglacial landscapes worldwide. Image 1 • Recent mass movement events significantly damaged archaeological landscapes around the High Arctic community of Siorapaluk. • Sudden onset was caused by heavy rainfall events amidst circumpolar shifts in precipitation. • Historical satellite and aerial images reveal the extent and acceleration of destructive processes. • The case of Siorapaluk helps predict the risk to sites in periglacial environments worldwide. [ABSTRACT FROM AUTHOR]