The September 2024 floods along Nepal’s Banepa–Bardibas Road, commonly known as BP Highway, resulted in one of the most severe transport infrastructure failures in the Himalayan region to date. These floods, triggered by an extreme three-day rainfall event (including a 24-hour deluge exceeding 300 mm at multiple stations), heavily damaged the 26 km stretch between Bhakundebesi and Nepalthok. Using chainage-level field reconnaissance, rainfall analysis, and a review of emergency response and rehabilitation measures, this study provides the first integrated documentation of the hazard cascade, infrastructure failures, and institutional responses along the severely impacted road section. The results reveal distinct failure modes, including complete washouts, retaining wall and toe protection collapses, and debris-induced blockages, driven by interacting flood processes (riverbank erosion and sediment surges). Despite early national flood alerts, preparedness remained reactive, causing severe bottlenecks; recovery efforts relied heavily on emergency diversions and temporary gravel tracks. International comparisons show that, while global authorities now embed climate risk into design standards, Nepal’s roadway network remains anchored in obsolete design return periods. This study provides the first integrated, chainage-level documentation of the hazard cascade, infrastructure failure typologies, and institutional response along a severely impacted Himalayan river-corridor roadway, combining field reconnaissance, rainfall analysis, and international benchmarking within a single corridor-scale analytical framework. The findings demonstrate that compound hazard interactions, particularly the amplification of flood impacts by quarry-induced channel constriction and systemic gaps in risk-informed planning are the defining drivers of infrastructure vulnerability in this and comparable mountain road corridors across South Asia.

Roadside slope failures persistently challenge mountainous developing countries where fragile geology, steep terrain, intense rainfall, and rapid road expansion amplify landslide risk. Nepal exemplifies this condition with recurrent slope failures disrupting transport despite existing policies and technical guidelines. This study systematically assesses Nepal’s roadside slope management framework as a representative case of slope-risk governance in mountainous regions. The study reviews national policies, analyzes ten roadside landslide cases, examines maintenance and loss datasets, and surveys 40 professionals to evaluate lifecycle governance effectiveness using Partial Least Squares Structural Equation Modeling (PLS-SEM). The results reveal a pronounced lifecycle imbalance: while policy/design guidance is relatively developed, construction-phase safeguards, such as exposure-time limits for newly excavated slopes absent in Nepal’s standards but typical in international practice to mitigate rainfall-triggered failures, and operational maintenance provisions remain weakly regulated. Economic analyses and evidence from extreme events indicate that direct costs associated with road closures are escalating. PLS-SEM results indicate that integrated risk planning and policy awareness significantly enhance management effectiveness, whereas institutional capacity alone has a limited direct impact. The findings highlight the need for comprehensive, enforceable, lifecycle-oriented, and climate-adaptive slope management emphasizing preventive investment, construction-phase control, and applied policy knowledge, with potentially transferable relevance for other mountainous developing regions.

Recurrent slope failures along Himalayan Road corridors cause substantial infrastructure damage and loss of life, yet systematic forensic investigation of individual failure sites remains rare in Nepal. This study presents an integrated forensic geotechnical–geophysical investigation of the Sirubari landslide, a repeatedly active failure site located on the Kali Gandaki Road corridor (Myagdi District, Lesser Himalayas, Nepal), to determine its failure mechanism, identify primary causal factors, and recommend evidence-based mitigation measures. Three two-dimensional Electrical Resistivity Tomography (ERT) profiles using the Wenner electrode array configuration were conducted across the landslide zone, supplemented by two rotary core boreholes (BH-1 and BH-2) each drilled to 15 m depth with Standard Penetration Testing and comprehensive laboratory characterization. ERT inversion revealed a complex subsurface stratigraphy comprising sandy colluvial deposits exceeding 21 m in thickness overlying saturated fractured phyllite bedrock, with multiple slip surfaces identified at depth. The colluvial mass is predominantly sand (73–97

An earthquake with a moment magnitude of MW 5.7 struck western Nepal (with the epicenter in Ramidanda, Jajarkot District) at 18:02 GMT (11:47 pm local time) on November 3, 2023. Jajarkot, Rukum West, and Salyan were the most affected districts, with a death toll of 154 and over 366 injuries. Overall, 26,557 residential buildings completely collapsed, and 35,455 others sustained partial damage. Immediately after the earthquake, the authors undertook a field investigation and visited the affected areas. Geotechnical and structural aspects of this earthquake are briefly discussed in this paper. Geotechnical aspects, such as landslides along highways, rock falls, pavement cracking, and site amplification effects, which considerably influenced damage patterns in many areas, are briefly examined. Structurally, most of the affected buildings were made of unreinforced masonry and adobe, with a few being reinforced concrete. The failure mechanisms of these buildings are briefly explained. The findings highlight the critical need to enforce rigorous building codes and standards to mitigate seismic risk in vulnerable regions like Nepal. Additionally, the study aims to enhance earthquake preparedness and provide valuable insights for engineers and policymakers to reduce risks and improve disaster resilience.

Roadside landslides pose critical challenges to transportation infrastructure in Himalayan corridors, threatening connectivity to remote communities and causing significant economic losses during monsoon seasons. Yet systematic investigation frameworks integrating geophysical characterization with quantified stability assessment and mitigation evaluation remain limited. This study demonstrates such a framework applied to the Baluwatar landslide along the Khodpe-Chainpur Road (NH-64) in Bajhang District, Sudurpashchim Province, Nepal. This study employed Electrical Resistivity Tomography, borehole investigations, and Limit Equilibrium modeling to characterize subsurface structures and conduct slope stability analyses. Results identified critical low-resistivity zones, indicating water-saturated colluvial deposits and potential slip surfaces located at 25-30 m depth. Boreholes confirmed loose, sandy colluvium and a shallow groundwater Table (1-2 m). Under simulated monsoon conditions, the current Factor of Safety (FOS) values are 1.179 (hillside) and 1.124 (valley side), denoting marginal stability driven by saturation and road undercutting. Modeled mitigation strategies, including high-strength mesh with soil nailing, catch drains, and a gabion retaining wall, successfully raised the FOS to 1.969 (hillside) and 1.328 (valley side), demonstrating significant stability improvement. This framework provides a scalable Disaster Risk Reduction approach for global road corridors in steep mountainous terrains, emphasizing the importance of groundwater management for stability.

Recurring roadside landslides along Himalayan highway corridors pose a critical threat to infrastructure and livelihoods, yet paired investigations of distinct co-located failure modes remain scarce. This study investigates two active landslides, Khamvitta and Lete Khola, along the Kaligandaki Corridor (NH-48), Nepal, with Khamvitta directly tested in the field and laboratory and Lete Khola assessed by geophysics alone. Two-dimensional Electrical Resistivity Tomography (ERT) was deployed at both sites; Standard Penetration Tests, Dynamic Cone Penetration Tests, and laboratory characterisation were additionally conducted at Khamvitta, while Lete Khola relied solely on a single ERT profile, with shear strength parameters drawn from published analogues to inform limit equilibrium modelling. Low-resistivity zones (< 100 Ωm) were interpreted as saturated clay-silt horizons and validated against borehole data at Khamvitta. Monsoon-season SEEP/W-coupled SLOPE/W modelling gave a factor of safety (FOS) of 1.071 at Khamvitta and two critical surfaces at Lete Khola, FOS = 0.724 (upper) and 1.298 (lower), confirming groundwater-induced effective stress reduction as the principal destabilising mechanism. Mitigation comprising subsurface drains, anchored RCC walls, gabion walls, soil nailing with 3D mesh, and slope re-profiling improved the FOS to 1.847 at Khamvitta, 1.378 (upper), and 2.357 (lower) at Lete Khola respectively. The study demonstrates that comparable hydrological forcing produces fundamentally different failure modes, shallow rotational failure in phyllitic colluvium at Khamvitta and compound translational failure in cohesionless alluvium at Lete Khola, governed by contrasting lithology, slope geometry, and anthropogenic modification; the Lete Khola interpretation is a literature-constrained conceptual model. These findings offer transferable guidance for roadside slope management across trans-Himalayan corridors.

In the Himalayas, communities face significant landslide threats, which emphasize the critical need for effective, data-driven risk assessment frameworks. This study introduces a machine learning system designed for mapping landslide susceptibility and vulnerability in Doti District, Nepal. We compiled a comprehensive inventory of 1,147 confirmed landslides from 1997 to 2023, along with 13 causative factors that were carefully screened for multicollinearity; all VIF values ranged from 1.04 to 2.94. We evaluated four different models: Logistic Regression, Support Vector Machine, Random Forest, and XGBoost. Among them, XGBoost achieved the highest AUC of 0.96, an accuracy of 88.5

Nepal receives about 80% of its annual monsoon rainfall between June and September, with the heaviest rainfall occurring in the middle 2 months. Although rainfall-induced landslides and localized damage are common, the record-breaking 3-day rainfall from September 26 to 28, 2024, which caused economic losses exceeding 1% of the entire GDP of Nepal and 250 fatalities, is unprecedented. Most of the damage was concentrated in the Kathmandu Valley and surrounding areas, including Kavrepalanchok and Dhading. Twenty-five rainfall stations in central Nepal recorded their highest-ever 24-h rainfall during this event. This study provides observations of landslides and debris flows, identifies causative factors, and outlines short- and long-term strategies to enhance resilience in the Kathmandu Valley, which could also be applied to the surroundings and elsewhere with similar geology. Key causative factors include intense rainfall, pre-saturated slopes, weathered rock masses, poor road construction, unregulated sand mining, and reduced rainfall thresholds due to earthquake preconditioning. This study recommends integrated short- and long-term mitigation measures to address landslide and debris flow risks in the Kathmandu Valley. These include community awareness, real-time weather warnings, hazard mapping, structural and bioengineering interventions, and improved drainage. Policy actions involve revising legal frameworks, regulating mining, strengthening watershed management, and enforcing land use planning. Emphasis is placed on combining nature-based and engineered solutions tailored to Nepal's diverse physiography and rainfall patterns, supported by institutional coordination and capacity building at the local level.

On November 3, 2023, at 23:47 local time, a MW 5.7 earthquake struck Barekot in northwest Nepal at a depth of approximately 12 km. Although the region has been predicted to experience a major earthquake, this moderate-sized earthquake was the most severe seismic event in 518 years. Despite its relatively low magnitude, the earthquake caused significant damage, resulting in 154 deaths and the collapse of over 26,557 houses. This underscores the critical need for post-earthquake reconnaissance to identify vulnerabilities and improve mitigation strategies before more severe events occur. Recognizing this importance, a detailed reconnaissance was conducted from November 6 to 9, 2023, focusing on the geotechnical impact of the earthquake. Based on the field observations, this paper discusses several geotechnical issues triggered by earthquakes in the region, including shallow landslides, rockfalls, and structure damage to flexible pavement and retaining walls. The study also explores the potential triggering mechanisms for the rock fall and discusses possible remedial techniques. Additionally, the influence of the local site effect on the extent of damage was examined. Remote sensing techniques were employed to detect post-earthquake ground patterns and land use changes using Sentinel-1 and Sentinel-2 images, respectively. The Sentinel-1 images were analyzed using the persistent scattering interferometric synthetic aperture radar (PS-InSAR)-based method, and the Sentinel-2 images were analyzed via the Google Earth Engine (GEE). By assessing these geotechnical impacts, this study aims to enhance earthquake preparedness in the future and provide valuable insights for engineers and policymakers to reduce risks and improve disaster resilience.

Kathmandu Valley, the capital region of Nepal, is a heavily populated, rapidly growing and haphazardly urbanized metropolis of the country, primarily seated upon lacustrine and fluvial origin deposits. The valley is situated in an earthquake-prone zone with a long history of catastrophic earthquakes, so the valley deposit is vulnerable to intense ground shaking and wide-area liquefaction during mid to major earthquakes. Although a few localized geotechnical studies have been conducted in the valley, holistic understanding, modelling, and geotechnical soil characterization are not well documented. In this study, based on the geotechnical properties of a large number of borehole materials, we put efforts in characterizing the Kathmandu Valley soil, 3D modelling of subsurface lithology and stratigraphy, mapping the geotechnical properties, and finally shedding light on the geotechnical characteristics of the valley subsoils. For this, we collected and analysed more than 400 borehole-based geotechnical investigation reports, and also specifically investigated 10 new test borehole locations and measured the standard penetration test (SPT-N) values along with the required laboratory tests. The methods for geotechnical characterization and result interpretation include Rockworks 3D model of lithology and stratigraphy and graphical and statistical presentation of the index properties (i.e. grain size distribution, dry unit weight, plasticity parameters, natural moisture content, Atterberg limits, etc.), consolidation parameters, shear strength, SPT-N value, and shear wave velocity. We basically focus on highlighting the statistical and spatial variations of the above soil properties with the depth. Moreover, a few correlations of the geotechnical properties are also established. We expect the findings of this study will aid structural and foundation engineers in studying foundations, cost estimation of geotechnical investigations, and planning and implementing various civil engineering projects.

Roadways are the most common mode of transport because they offer last-mile connectivity and are user friendly. In hilly and mountainous regions, however, most roads are vulnerable to landslides, posing significant disruption in traffic movement as well as risk to human life and property. Understanding these road vulnerabilities is important for ensuring the smooth operation and safety of transportation service. This paper aims to explore the risk of landslides to road and road infrastructure along the Narayanghat–Kathmandu road section in Nepal, and for this, we have taken into account 11 landslide conditioning factors and created a landslide susceptibility map of the study area, employing the analytical hierarchy process (AHP) in the geographic information system (GIS) platform. The performance of the susceptibility model was evaluated by area under the receiver operating characteristic (ROC) technique using 122 historical landslide inventory datasets. Subsequently, considering seven critical road infrastructure elements at risk, landslide vulnerability map was prepared for the target roadway. By combining susceptibility and vulnerability maps, a disaster risk map was generated. From the obtained results, it was understood that several key components of the road infrastructure in the study area are located at high-risk zone, which include four bridges, thirty two culverts, thirty two retaining walls, twelve safety blocks, and two delineators. The significance of this study is at mitigating the adverse impacts of landslides on roadway infrastructure and improving the safety and reliability of transportation network in mountainous regions.

The 2019 windstorm in Nepal struck villages in the Bara and Parsa districts, central-south of Nepal, on March 31, 2019, causing widespread devastation. The storm, rated five (5) on the Enhanced Fujita Scale, cut a 33 km swath through central-southern Nepal. In total, 1,452 private houses were destroyed, while 1,373 others suffered partial damage. The tragic storm claimed 28 lives and left 1,155 individuals injured. The impact of this tragedy extended to nearly 3,000 families. Immediately after the storm, a comprehensive damage assessment framework was developed, and a field reconnaissance study was conducted to understand the damage distribution and building failure mechanisms under tornado wind loads. Common damage modes observed were roofing material damage, roof-to-wall connection failure, and brittle masonry wall failures in the affected areas. This paper presents the lessons learned from damage to the building infrastructure during the 2019 windstorm in Nepal. Examined buildings underscore the critical need for design alternatives and sustainable retrofits, emphasizing load path integration and strong roof-to-wall connection. Strengthening the building envelope can significantly enhance its resilience against storms and other disasters prominent in the region. This study highlights the importance of proactive measures to safeguard vulnerable communities against natural hazards and offers insights into resilient building construction technology.

On November 3, 2023, a local magnitude ML 6.4 (moment magnitude, MW 5.7) earthquake struck the Ramidanda epicenter (28 degrees 50'24'' N, 82 degrees 11'24'' E) in Jajarkot, Nepal, at 11:47 p.m. local time (18:02 GMT), with a maximum intensity VI on the Mercalli Intensity Scale. Continuous aftershocks further devastated partially affected villages in Jajarkot, West Rukum, and Salyan. This seismic sequence stands as one of the most destructive earthquakes in Nepal since the 2015 Gorkha Earthquake, with a total death toll of 154 and over 366 people injured. The earthquake caused the complete collapse of 26,557 houses, while 35,455 houses were partially damaged. Postearthquake reconnaissance showed that the damage to masonry buildings in the affected areas was mainly due to poor construction quality, degraded construction materials, and noncompliance with codal provisions. Although reinforced concrete buildings in proximity to the main shock epicenter suffered minor damages, many of the affected structures were found to lack appropriate design or construction adherence to the national building code of Nepal. This paper, based on the postearthquake field visit, aims to present the structural damages in buildings incurred during the earthquake, discussing case histories of the affected buildings, their patterns, and the failure mechanisms. The findings highlight the critical need to enforce rigorous building codes and standards to mitigate seismic risk in vulnerable regions like Nepal.

Understanding the underlying causes of flood disasters is essential not only for developing effective flood management strategies but also for evaluating past policies and mitigation efforts. This study investigates the multi-dimensional causes and impacts of the increasing flood disasters in the Kathmandu Valley and the surrounding Roshi catchment, with a specific focus on the unprecedented September 2024 floods. Using a diverse range of data sources-including field observations, open-ended interviews, published studies and reports, remote sensing, socio-economic and hydro-meteorological data, as well as institutional, legal, and policy frameworks-we identify key factors contributing to the rising flood risk in and around the valley. The causes of flooding were broadly categorized into four main areas: catchment characteristics, anthropogenic activities, hydro-meteorological factors, and policy and institutional frameworks. The extreme rainfall events of September 2024 and the resulting floods further exposed the Kathmandu Valley's vulnerability, causing over three dozen fatalities and millions in economic losses. Unlike previous years, the flood impacts were exacerbated by debris flows and landslides from surrounding hillslopes, along with sediment contributions from mining sites and encroached riverbanks, intensifying the severity of inundation. Despite early warnings of heavy rainfall from concerned agencies, inadequate preparedness and response significantly amplified the disaster's impact, revealing critical gaps in Nepal's disaster management framework. Instead of a one-size-fits-all approach, effective flood management in the Kathmandu Valley requires a collaborative, multi-dimensional strategy tailored to its unique challenges. The September 2024 floods underscore the urgent need for systemic reforms in urban planning, policy reforms and enforcement, inter-agency collaboration, strengthened local government, and disaster risk management. Our analysis provide critical insights for enhancing flood resilience and improving future flood risk management strategies in a holistic manner.

Landslide disasters in Nepal are widely reported to have increased in the last decade, but there has been limited on trends in landslide occurrence in Nepal from 2011 to 2020. This study presents the spatio-temporal distribution and trends of landslide disasters in the Nepal Himalayas and identifies landslide-prone areas. Landslide disaster data was collected to assess annual variations, investigate the relation between rainfall and landslides, describe the landslide distribution pattern, conduct statistical analysis, and predict landslide causes and triggering factors. The dataset suggests that the overall trend in landslide disasters in Nepal from 2011 to 2020 is increasing, with a high level of variability in the number of landslide disasters from year to year, depending on several factors. Results show that landslide events were clustered in space and time, with 93.26

On 3 November 2023, a moment magnitude (MW) 5.7 (Local Magnitude, ML6.4) earthquake struck the western region of Nepal, one of the most powerful seismic events since 1505 in the region. Even though the earthquake was of moderate magnitude, it caused significant damage to several masonry buildings and caused slope failures in some regions. The field reconnaissance carried out on 6–9 November by the study team, following the earthquake, conducted the first-hand preliminary damage assessment in the three most affected districts—Jajarkot; West Rukum; and Salyan. This study covers the observed typical structural failures and geotechnical case studies from the field study. To have a robust background understanding, this paper examines the seismotectonic setting and regional seismic activity in the region. The observations of earthquake damage suggest that most of the affected buildings were made of stone or brick masonry without seismic consideration, while most of the reinforced concrete (RC) buildings remained intact. Case histories of damaged buildings, the patterns, and the failure mechanisms are discussed briefly in this paper. Significant damage to Khalanga Durbar, a historical monument in Jajarkot, was also observed. Medium- to large-scale landslides and rockfalls were recorded along the highway. The motorable bridge in the Bheri River suffered from broken bolts, rotational movement at the expansion joint, and damage to the stoppers. The damage observations suggest that, despite the existence of building codes, their non-implementation could have contributed to the heavy impact in the region. This study highlights that the local population faces a potential threat of subsequent disasters arising from earthquakes and earthquake-induced landslides. This underscores the necessity for proactive measures in preparedness for future disasters.

Sustained efforts and investments in different sectors are essential for the overall development of a region. Various studies around the globe underscore the importance of investment in road transport infrastructure in many developing countries to achieve their development targets. The relationship between infrastructure investment and economic growth is often found to be inconsistent. This ambiguity leads to a lack of consensus on an appropriate scale of investment required among the policy makers. So, it is often necessary to depend on empirical evidence by developing causality direction, which significantly contributes to policy implications in developing countries. The objective of this analytical study is developing a relationship between the road transport infrastructure and economic growth of Nepal. For this, relevant data from 1998 to 2022 were used to perform a unit root test and determine the order of integration, followed by cointegration analysis to determine the long-run relationship between the variables. In addition, the vector error correction model (VECM) was employed to find the direction of causality. The findings indicate unidirectional long-run causality from gross capital formation, exports of goods and services, expenditure on road transport infrastructures, and road length to the GDP of Nepal. Furthermore, the expenditure on road transport infrastructures is observed to have a short-run impact on economic growth. This study recommends that a suitable transportation policy should be implemented to boost investment on road transport infrastructures to achieve sustainable economic growth in Nepal-like developing nations.

Kathmandu Valley, the capital of Nepal, is a highly populated and rapidly urbanised area of the country built upon lacustrine and fluvial origin deposits. Because the valley deposit is located in an earthquake-prone zone with a long history of catastrophic earthquakes, it is vulnerable to numerous geohazards like liquefaction. Although a few localized geotechnical studies have been conducted in the valley, holistic understanding, modelling, and geotechnical soil characterisation are seldom documented. This study attempts to characterize the Kathmandu soil based on geotechnical properties using statistical analysis approach. We have collected and analysed more than 400 geotechnical investigation reports and bored 10 test locations. Statistical analysis and representation of index properties, consolidation parameters, shear strength, SPT-N value, and shear wave velocity have been assessed in this paper. These findings can aid structural and foundation engineers in studying foundations, cost estimation of geotechnical investigations, and planning and implementing various civil engineering projects.