29 Jun 2026

Automated Workflows for Airborne Lidar and Photogrammetry Snow Depth Analyses

Abstract: Lidar and photogrammetry techniques provide highly accurate methods for mapping snow depth distribution. However, postprocessing point clouds for snow depth estimation is more complex compared to other earth science applications. This paper presents ice-road-copters (IRC), an open-source Python toolkit that facilitates processing and georeferencing of lidar and photogrammetry point clouds. Case studies demonstrate the tool’s utility across different sensors and platforms over a complex mountainous study area. Results show that a well-configured digital elevation model (DEM) filter effectively removes most noise and outliers from point cloud data. The Simple Morphological Filter (SMRF) generally perform well for ground segmentation but optimal results across diverse terrains may require site-specific tuning, particularly of the elevation threshold and scalar parameters in more complex landscapes. Different methods, including manual depth measurements or snow-free features, can be used to coregister DEMs, reducing vertical errors, eliminating large bias and achieving comparable accuracy to using exposed control surfaces. Derived snow depth rasters showed strong agreement with in situ probe measurements—root-mean-square error (RMSE) of less than 16 cm. Overall, IRC simplifies the transformation of raw point clouds into high-resolution DEMs and value-added snow products, facilitating efficient multitemporal analysis to support military and hydrology applications.

10 Oct 2025

Standard Operating Procedures for the Site Selection, Design, and Maintenance of Low-Water Crossing Linear Infrastructure in Cold Regions

Abstract: Low-water crossings (LWCs) are critical components of DoD infrastructure in Alaska and other cold regions, yet their effective siting, design, construction, and maintenance are challenged by remote locations, limited environmental data, seasonal hydrology, and complex terrain. Harsh winter conditions, rapid spring melt, and freeze–thaw cycles introduce hazards such as ice-related scour, debris loading, and variable streambed stability. In cold-region operational areas, natural processes such as permafrost degradation, shifting hydrologic regimes, and sudden flood events from glacial or thermokarst activity further increase risk to infrastructure performance and longevity. This report addresses these challenges by consolidating best practices and mitigation strategies for LWC implementation in cold environments. Drawing on technical literature, input from land managers, and existing agency standards and SOPs, the report identifies key considerations for improving LWC resilience. These include accounting for ice forces, complex geotechnical challenges, sediment transport, and the use of appropriate materials to name a few. By framing LWCs within a systems-based approach to site selection and engineering design, the report provides guidance for supporting safe and sustainable operations across Arctic and Subarctic training environments. It serves as a technical resource for DoD planners and engineers tasked with managing infrastructure in cold regions.