INTRODUCTION1.1 Background Supraglacial channels exhibit meandering planform dynamics driven by thermal erosion and subglacial topography. Thermal erosion rates are governed by flow speed, water temperature and channel aspect ratio. Supraglacial streams form an important part of the glacial hydrological system as they transport both meltwater and energy over the surface of glaciers and ice sheets (Pitcher and Smith 2019;Rippin et al. 2015;Smith et al. 2015). As such, they play an important role in the surface mass balance of glaciers and ice sheets, as recent research at the Greenland Ice Sheet has shown (Enderlin et al. 2014). Supraglacial channels can range from a few centimeters to tens of meters in depth and width (Germain and Moorman 2016), transporting meltwater either to the glacier margins or into moulins (vertical conduits transporting water to the subsurface) as well as into supraglacial lakes (Chu 2014). Recently, supraglacial discharges have been shown as a key physical driver of the observed changes in ice sheet dynamics via rapid drainage events into the subsurface (Chudley et al. 2019). Despite the recognition of their importance in glacial hydrology supraglacial systems remain understudied, and fundamental supraglacial fluvial science remains at a nascent stage of development (Gleason et al. 2016).Supraglacial streams have several differences from their terrestrial counterparts: They are formed in ice rather than rock or gravel. Fundamentally, this is because they lack sediment (Knighton 1981), they have no vegetated banks, and adjust their channel form rapidly. This is because supraglacial streams are subject to thermal, rather than mechanical erosion as the main driving process, including significant diurnal discharge variations (Jarosch and Gudmundsson 2012).