7 Apr 2026

Vehicle and Unpiloted Aerial System Interferometric Synthetic Aperture Radar Data Collection and Processing

Abstract: Interferometric synthetic aperture radar (InSAR) systems have a wide breadth of cold regions science and engineering applications such as determining snow water storage, permafrost thaw induced subsidence and frost heave of the active layer, and ground slope and infrastructure stability in permafrost dominated regions. Here, we present project planning, data collection, and processing workflows from two L-band InSAR systems, L-band SAR (GS-L) and UAS-mounted (GLSAR). The GS-L platform is integrated on a mobile, ground-based platform while the GLSAR is integrated on an uncrewed aerial system (UAS). We describe the postprocessing steps to produce radar back-scattered power and interferograms for the analysis of subsurface and near-surface phenomena. These steps are common to all the sensors discussed in this report and include kinematic postprocessing of the sensor positions, focusing on the raw radar returns in range and azimuth to form the radar image, and calculating the interferometric phase between acquisitions. With examples from each platform, we demonstrate the utility of these InSAR sensors and discuss acquisition scenarios in which either ground-based or UAS-borne systems may deliver higher-quality information from one another.

19 Mar 2026

Compressed Snow Blocks: A Proof-of-Concept Study for Adapting Earth Block Technology for Cold Regions

Abstract: Snow construction plays a crucial role in military operations in cold regions, providing tactical fortifications, thermal insulation, and emergency infrastructure in environments where conventional building materials are scarce or require extensive infrastructure to support. Research into optimized snow compaction techniques has informed the design of snow-based protective structures, runways, and shelters. This study tested whether a conventional compressed earth block (CEB) machine could be used to produce compressed snow blocks (CSBs) suitable for construction applications in cold environments. The machine successfully formed CSBs with relatively consistent dimensions (i.e., block height), demonstrating feasibility and reliability in shaping snow for structural purposes. Density measurements of the snow blocks were more consistent with ice, indicating potential viability in load-bearing applications, but suggesting that the pressure applied during production may not be necessary to reach sufficient block strength depending on its intended end-use. While mechanical strength was not assessed, these initial findings support further investigation into optimizing this new snow compaction technique, the material properties, and block durability under environmental stressors (e.g., temperature fluctuations). Additional testing and development are required to refine this approach for faster, more efficient snow compaction for sustainable construction in cold regions.

19 Mar 2026

Arctic and Subarctic Zonal Characterization and Operational Thresholding (AZCOT)

Abstract: The US military develops and updates environmental parameters specified for the sustainment of operations throughout the world. These requirements are generally based on environmental data providing a baseline of temperature, wind, and precipitation expectations for each location. Observational data for Arctic regions is limited because of the remote and sparsely occupied geographical conditions. To address the need for updating these requirements, a 30-year analysis of meteorological conditions was conducted using a European Centre for Medium-Range Weather Forecasts (ECMWF) global reanalysis dataset over the Arctic and Subarctic region, defined by latitude 60°–90° North for this project. Raw hourly datasets were acquired, and the minimum temperatures, maximum wind speeds, maximum snow depths, and averages were determined over the period 1991–2020 between the months of October and March for each parameter. These were then visualized with geospatial analysis, producing a variety of maps designed to assist with the classification of parameters in Arctic zones of operation across a range of temporal resolutions. Finally, a review of operational limits for military equipment was conducted to match northern zones of operation with suitable capabilities dependent on environmental conditions.

23 Feb 2026

Ice Cutting and Removal for Cold Weather Improved Ribbon Bridge (IRB) Crossings

Frozen rivers provide an obstacle for any military force, as ice impedes the use of Improved Ribbon Bridges (IRBs) or other bridging vehicles. Finding an efficient way to cut and remove ice to allow for the emplacement of bridging assets is critical. The US Army Cold Regions Research and Engineering Laboratory’s (CRREL) Cold Weather IRB team went to Camp Grafton, North Dakota, to collect data for the North Dakota National Guard who were conducting a frozen wet gap crossing in February of 2022. Both quantitative and qualitative data were collected to evaluate strategies for ice cutting, removal, and IRB placement. After ice cutting and removal, an IRB bay was successfully placed in the frozen pond. Laboratory tests were conducted in March 2022 to examine different chainsaw chains for cutting an ice sheet grown in the Geophysical Research Facility (GRF) at CRREL. Chainsaws were determined to be an effective tool for cutting ice, and the speed and comfortability of different chains were documented. The data collected from this project will help to drive the North Dakota National Guard creation of a winter bridging course and will be used to update the Army’s Tactics Techniques and Procedures (TTPs) for cold weather bridging operations.

8 Dec 2025

Improved Prediction of Soil Thermal Properties Using Gated Recurrent Unit Neural Networks

Abstract: Frost actions, such as frost depth penetration and thaw weakening, are damaging to airfields and roadways in cold regions. Machine learning techniques, such as recurrent neural networks, have been applied to this problem, but with a large focus on long short term memory (LSTM) neurons. Gated recurrent units (GRUs) are similar to LSTM neurons in terms of accuracy, but are more computationally efficient, and have yet to be applied to predicting soil thermal properties. Using a hyperparameter search, an optimal architecture for a recurrent neural network based on gated recurrent units was identified. A general model using temperature, thermal conductivity, and volumetric moisture content was found to predict temperatures effectively, having an error of less than 0.25°F across all depths. For predicting thermal conductivity, a model including temperature but not moisture content was found to be effective. For moisture content, the results were inconclusive as both models were affected by similar errors. Overall, the GRU-base recurrent neural networks were found to work well for predicting soil thermal properties in high-plasticity clays, and it is recommended to further expand the training datasets to include other frost-affected soil types.

24 Nov 2025

Ice Demolition Techniques—Rapid Improved Ribbon Bridge Placement and Enemy Forces Denial: Using Traditional Military Explosives Under Ice

Abstract: As the United States military focuses on furthering their lethality across cold regions, developing new techniques for equipment usage is necessary. On 19 March 2025, the US Army Engineer Research and Development Center–Cold Regions Research and Engineering Laboratory (ERDC-CRREL) collaborated with the Army Engineers from the 50th Multi-Role Bridge Company (MRBC), 6th Brigade Engineer Battalion (BEB), and Sapper Leader Course (SLC) to determine whether explosives can be used for Improved Ribbon Bridge (IRB) placement in ice-laden environments. As the US Army adapts to meet the evolving threats from foreign adversaries, there is an increased tactical necessity for enhanced bridging capabilities in frozen terrain. Developing an expedient method of removing ice from these waterways and placing IRBs for easy crossing of heavy military equipment is essential. Through this experiment it was determined that the use of a 40 lb cratering charge primed with M152 boosters significantly fractures the ice cover expeditiously. However, the ice expulsion rate found in this experiment was insufficient for IRB deployment which requires 60% expulsion rate. Although the experiment fell short of IRB requirements, it proved to be an efficient and effective countermobility tool for units who use frozen water ways as avenues of approach.

4 Nov 2025

Preliminary Evaluation of Selected Expeditionary Shelter Systems in a Subarctic Environment: Phases I and II of Cold Weather Testing

Abstract: The warming of high latitude regions is causing geopolitical concerns and spurring increased human presence across the Arctic. Potentially, these situations require only a short-term occupation necessitating tested and developed expedient infrastructure. Operating requirements for high latitude conditions are vastly divergent from temperate locations. Shelters must be able to provide habitable conditions at temperature down to −60°F, withstand 100 mph wind speeds, and support 25 lb/ft2 of snow load. Although great advances have been made in providing efficient and comfortable Arctic infrastructure since the onset of the Cold War, significant work remains to further increase efficiencies and adapt to changing weather parameters. To address infrastructure technology gaps, the US Army Corps of Engineers–Engineering Research and Development Center (USACE-ERDC) established the Arctic Infrastructure Research Group (AIRG). Over two phases of investigation, the AIRG evaluated three selected expeditionary shelter systems at its Arctic Infrastructure Research Center (AIRC) in Fairbanks, Alaska during the winters of 2020–2021 (Phase I) and 2021–2022 (Phase II).

4 Nov 2025

Airfield Assessments to Identify Improvements in Support of Arctic Military Operations: Arctic Airfields Assessment

Abstract: This report examines current airfield capabilities in Alaska and Greenland as they pertain to the strategic priorities of the Northern Aerospace Defense Command (NORAD) and US Northern Command (NORTHCOM) in support of needs identified in the 2024 DoD’s Arctic Strategy. With increasing activity and competition in the circumpolar region, airfields in Alaska and Greenland play a vital role in enabling homeland defense, supporting domain awareness needs, and enabling rapid response operations. This report highlights key airfields across Alaska and Greenland, focusing on their current readiness to support NORAD-assigned airframes such as the C-17, C-130, F-15, F-16, F-22, F-35A, KC-10, KC-135 and KC-46A. It assesses currently available infrastructure, operational resilience, airfield suitability and current condition, weather considerations, and logistics sustainment. Gaps in infrastructure readiness and logistical necessities for different airframes are identified. Recommendations are provided to bolster airfield operational capabilities as they pertain to the NORAD mission, and to ensure Arctic basing remains a credible enabler of NORTHCOM’s mission to defend the US and deter threats across the circumpolar region.

10 Oct 2025

Standard Operating Procedures for the Site Selection, Design, and Maintenance of All-Season Roads Linear Infrastructure

Abstract: Planning, designing, constructing, and maintaining all-season roads in cold regions requires navigating complex environmental, hydrologic, and geomorphologic challenges. Harsh conditions, such as permafrost, frost-susceptible soils, muskeg, and extreme cold, are compounded by limited data availability, remote locations, and fragile ecosystems. Recent Arctic strategies across the DoD have identified changing weather patterns as significant threats to infrastructure, operations, and training land management in these regions. Key risks include degrading permafrost, changes in precipitation intensity and duration, and the loss of soil bearing capacity in saturated soils, all of which are examined in detail. As the Department of Defense expands Arctic training capabilities, infrastructure investments across Alaska must balance operational goals with sustainability and resilience. This report synthesizes the military’s typical methods for constructing roads in contingency environments, identifies practices used in the construction of the Alaska-Canada Highway, and draws from consultations with training land managers, a thorough literature review, and active engineering research. The report highlights the importance of holistic design that prioritizes longevity, environmental conservation, and safety by addressing cold-region challenges, mitigation strategies, and best practices. This resource is indispensable for military units and infrastructure planners tasked with navigating the complexities of cold-region infrastructure construction and operation.

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.