Active subglacial lakes in the Canadian Arctic identified by multi-annual ice elevation changes

Abstract. Subglacial lakes influence glacier hydrology, dynamics, and mass balance; however, they are poorly documented outside the polar ice sheets. Here we use high-resolution digital elevation models from 2011 to 2021 and perform regression analysis to characterize 37 subglacial lakes (35 of which are newly identified) across the Canadian Arctic, a region that loses more than 50 gigatonnes of glacier ice yearly. These lakes have an area of 0.3–48.5 km² and influence surface elevation by 10–150 m, corresponding to a water volume of 0.003–4.5 km³. We classify them into (1) classic subglacial lakes, (2) terminal subglacial lakes at places where two glacier termini converge and coalesce, and (3) partial subglacial lakes with an area of open water at the ice margin. Types 2 and 3 are new and are nearly exclusive in the Canadian Arctic. Lake activities negatively correlate with regional mass balance, implying a need for fine-scale monitoring in the era of accelerated glacier loss.