Multi-year evolution of 75 snow and ice deposits in Schachtdolines and Shafts of recently deglaciated karst terrain: Observations from Mount Canin-Kanin, Julian Alps, Europe

Abstract

Dolines and shafts are common geomorphologies in karst landscapes. When affected also by glacial processes, they are considered an example of glaciokarst landform. In high alpine karst, their typical vertical shape lends itself particularly well to the formation of snow and ice accumulations that can survive the ablation season, potentially becoming perennial. This study analyses the 12-years changes of several permanent snow-ice deposits in Schachtdolines and Shafts (SIDS) and compares them with the mass balance of surrounding external ice bodies. According to recent studies and in contrast with the rest of the Alpine glaciers, ice masses of the area are resilient to climate change and show a slightly positive mass balance in the last decade. The presence of a long term mass balance monitoring program provides an excellent basis for a robust comparison with 75 selected SIDS, all located in the Mount Canin-Kanin massif, in the Julian Alps. Six airborne LiDAR surveys performed from 2006 to 2018 at the end of the ablation season allowed accurate calculation of thickness and volume changes. The measured differences show a general increase in thickness of the SIDS with more than one meter gain, although multi-annual observed variability between the sites is high. The observed 2006–2018 positive mass balance is in agreement with the external cryosphere although SIDS appear even more resilient than the external ice patches to both interannual weather variability and climate forcing.