Melting permafrost in high mountain areas represents a significant climate change driven hazard. This research shows the importance of this using novel photogrammetric methods coupled with a long observational record.

Understanding how sediment moves in rivers is fundamental to the shape of our landscapes and how they evolve. A key part of this understanding is measuring the size and shape of cobbles, pebbles and grains in the bed of a river. Often this measuring task is laborious and carried out by hand. However, this paper presents code and describes a method for measuring this using 3d point cloud data (from a laser scan for example) enabling the automation and rapid measurement.

Do earthquakes result in higher levels of sediment in rivers in the years following the event? There are several reasons to believe this could be the case. Previous studies have even provided evidence of increased sediment loads in mountainous areas after major earthquakes. However, a study by Graf et al. challenges this perspective. They demonstrate that despite the thousands of landslides triggered by the 2015 Gorkha Earthquake in Nepal, there were only minimal increases in coarse sediment in river channels during the subsequent years. Instead, the study reveals a different story. In June 2021, a single, exceptionally heavy rainfall event mobilized large volumes of sediment, leading to riverbed elevation by as much as 12 meters. This effect greatly overshadowed any sedimentary impact left by the earthquake along the river corridor. The study underscores that earthquake evidence may not always be found in the sedimentary records of alluvial areas. In high-mountainous regions, records of riverbed elevation may be strongly influenced by unique and localized events.

This paper presents a new way of quantifying geometries of drainage networks, moving beyond river long profiles to explore the complexity of planform branching river networks. Using the proposed length asymmetry metric, the paper demonstrates that complexity is correlated with landscape aridity, where arid landscapes have less complex networks compared to humid ones, suggesting this metric could be a new way of exploring the impact of climate on Earth's topography.