A FRAMEWORK FOR IN-STREAM LARGE WOOD IN SNOW AVALANCHE-PRONE LANDSCAPES

Large wood in rivers moderates flow dynamics, enhances sediment and nutrient storage, and supports biodiversity through habitat creation. While the significance of large wood in stream systems has been well documented, its behavior in avalanche-prone landscapes, where snow avalanches can contribute up to 1000 times more wood than background fluvial process, remains poorly understood. This project generates a framework for large wood at jam and reach-scale in avalanche-prone landscapes. We examined six avalanche-prone drainage basins in Colorado with visible snow avalanche large wood interactions. Study sites span a range of snowpack styles, glacial modification, and valley widths but have similar drainage areas and stream flows. We identified jams using high-resolution aerial imagery and used field observations to measure jam structure, orientation, hydrologic and sediment impacts, and vegetation interaction. From this, we created a framework of large wood jam types in avalanche-prone landscapes. This was combined with high-resolution aerial imagery and GIS to explore controls on jam types based on channel slope and width, stream order, and valley morphology. Our framework is the first to systematically address large wood in avalanche-prone landscapes and provides a basis for regional comparison of LW dynamics in high alpine settings. Future researchers can use this framework to investigate wood recruitment, longevity, and impacts on sediment and nutrient transfer in avalanche-prone landscapes.