Evolution of the firn pack of Kaskawulsh Glacier, Yukon: meltwater effects, densification, and the development of a perennial firn aquifer

Abstract. In spring 2018, two firn cores (21 and 36 m in length) were extracted from the accumulation zone of Kaskawulsh Glacier, St. Elias Mountains, Yukon. The analyzed for ice layer stratigraphy density compared against historical measurements made 1964 2006. Deep meltwater percolation refreezing events evident cores, with a total content 2.33±0.26 core liquid water discovered below depth 34.5 m. Together observed content, surface energy balance modelling indicate that Glacier retained about 86 % its years 2005–2017. For an average ablation 0.38 w.e. yr?1 over this period, estimated 0.28 refroze firn, 0.05 was as water, drained or ran off. refrozen is associated lowering 0.73±0.23 between 2005 2017 (i.e., drawdown has no mass loss). become denser more ice-rich since 1960s contains perennial aquifer (PFA), which may have developed past decade. This illustrates how be evolving response to climate change provides information required geodetic calculations, first documented PFA Yukon–Alaska region.