The imprint of erosion by glacial lake outburst floods in the topography of central Himalayan rivers

Abstract. In steep landscapes, river incision sets the pace of landscape evolution. Transport coarse sediment controls by evacuating material delivered to channels landslides. However, large landslide-derived boulders that impede bedrock erosion are immobile even in major runoff-driven floods. Glacial lake outburst floods (GLOFs) mobilize these and drive incision, yet their role regional-scale is poorly understood, largely because rarity. Here, we find a topographic signature consistent with widespread GLOF Nepal Himalaya. Our interpretations emerge from analysis normalized channel steepness patterns, knickpoint distributions, valley wideness. rivers glaciated headwaters generate GLOFs, valleys stay narrow relatively free sediment, often exposed erosion. turn, tributaries steep, allowing less efficient erosional regimes keep GLOF-driven incision. Where GLOFs frequent, more alluviated stalls. results suggest extent headwater glaciation may play an important Himalayan deserves attention future work.