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Glacier surges can create ice-dammed lakes when the advancing terminus blocks drainage. Such lakes are inherently unstable and can drain abruptly as glacial lake outburst floods (GLOFs), presenting a hazard to downstream populations and infrastructure in high mountain environments. We present satellite image analysis of the evolution of an ice-dammed lake formed by the 2018–20 surge of Shisper Glacier, western Karakoram. Our analysis identifies six phases of lake evolution. A large lake of up to 33.7 ± 9% million m3 formed in 2018–19, 2019–20, 2020–21 and 2021–22. In each case, the lake began to fill late in the year, reached a maximum size in May, and had completely drained between May and July, typically over 1–2 days. This analysis provides further evidence that GLOF hazards associated with lakes dammed by glacier surges can persist for several years after surge termination.

As global warming intensifies, the changes of glacial lakes in Xizang need to be carefully examined. Because of their special geographical location and physical characteristics, it is extremely liable to occur Glacial Lake Outburst Flood, which poses a serious threat to the surrounding residents, infrastructure and ecological environment. However, our knowledge about the specific distribution of glacial lakes across the region and their potential risks is still limited. Therefore, by using GIS spatial analysis and the parametric optimal geodetector method, we analyzed the spatio-temporal changes of glacial lakes in Xizang from 1990 to 2015, and the extent to which the annual total precipitation, annual average temperature, annual relative humidity and glacier area change factors affected the changes of glacial lakes. The statistics and analysis show that from 1990 to 2015, the growth rates of glacial lakes in quantity and area were 2.57% and 6.32%, respectively, while the number and area of moraine lakes increased by 18.96% and 28.45%, respectively. Through the analysis of the optimal parameter geographic detector, it is found that the change of glacier area has the greatest influence on the area and number of glacial lakes, with the q value 0.5006 and 0.1696, respectively. In the interaction detection, the interaction between temperature and glacier area change has the strongest explanatory power to the change of glacial lake area. The interaction of the precipitation and the glacier area change has the strongest explanatory power relative to the change of glacier lake number, and the relationship is non-linear. The change of glacial lake is the result of the interaction of various factors. This paper puts forward the quantitative evaluation of various factors and their interactions by using geographic detectors, and reveals the spatio-temporal distribution rule of glacial lakes in Xizang and its influencing factors. On the one hand, it can provide a scientific basis for the early warning and prevention of outbursts of flood from glacial lakes, and help to reduce disaster losses. On the other hand, this study also provides an important reference for the evolution of glacial lakes in the context of global climate change. [ABSTRACT FROM AUTHOR]

Climate change and rising temperatures are accelerating the rate of deglaciation in the Hindu Kush Karakoram Himalaya (HKH) ranges, leading to the formation of new glacial lakes and the expansion of existing ones. These lakes are often vulnerable to failure, posing a significant threat to downstream communities and infrastructure. Therefore, a comprehensive assessment of Glacier-Lake Outburst Flood (GLOF) hazards and risk assessment is crucial to evaluate flood runout characteristics and identify settlements and infrastructure that are exposed and vulnerable to floods, aiding in the development and implementation of risk reduction strategies. This study aims to simulate a GLOF event induced by the Shisper glacier lake in northern Pakistan, using the HEC-RAS, and to assess its impact on settlements, infrastructure, and agricultural land. For the hydrometeorological analysis of the GLOF event, topographic data from unmanned aerial vehicles (UAVs), stream profiles, discharge data, Manning's roughness coefficient (n), and land use/land cover (LULC) were analyzed using HEC-RAS and geographic information system (GIS). During the GLOF event on May 7, 2022, a maximum water depth of 6.3 m and a maximum velocity of 9.5 m/s were recorded. Based on the runout characteristics of this event, vulnerability and risk assessments have been calculated. The physical, social, and environmental vulnerabilities of the at-risk elements were evaluated using the analytical hierarchy process (AHP) and integrated with the hazard data to develop a risk map. The study identified the areas, infrastructure and settlements susceptible to GLOF hazard to support the development and implementation of targeted and evidence-based mitigation and adaptation strategies. [ABSTRACT FROM AUTHOR]

Anthropogenic climate change has led to rapid and widespread changes in the atmosphere, land, ocean, cryosphere, and biosphere, leading to more pronounced weather and climate extremes globally. Recent IPCC reports have highlighted that the probability of compound extreme events, which can amplify risk, has risen in multiple regions. However, significant gaps remain in our understanding of the drivers and mechanisms behind these events. This concept paper discusses compound events in the Asian region in the context of its unique and diverse geographical settings, and regional climatic features including the seasonal monsoons. Notably, Asia is the world's most disaster-affected region due to weather, climate, and water-related hazards. Therefore, an integrated understanding of how climate change will impact compound events in this region is essential for effective forewarning and risk mitigation. This paper analyzes three typologies of compound events in the Asian region, illustrating their regional complexity and potential linkages to climate change. The first typology pertains to compound floods, for example, the devastating floods in the Indus River Basin and adjoining Western Himalayas during 2022 caused by the combined effects of heavy monsoon rainfall, intense pre-monsoon heatwaves, glacier melt, and modes of climate variability. The second typology relates to compound heatwave-drought events that have prominently manifested in East and South Asia, and are linked to large-scale drivers of the land-atmosphere–ocean coupled system and local feedbacks. The third typology relates to marine extremes involving the compounding effects of ocean warming, sea-level rise, marine heatwaves, and intensifying tropical cyclones. We identify key knowledge gaps in understanding and predicting compound events over the Asian region and discuss advances required in science and technology to address these gaps. We also provide recommendations for the effective utilization of climate information towards improving early warning systems and disaster risk reduction. [ABSTRACT FROM AUTHOR]

The southeastern region of Tibet, which serves as the primary concentration area for marine-type glaciers, has fostered a multitude of glacial lakes that are highly sensitive to global climate change. Glacial lakes play a crucial role in regulating the freshwater ecosystems of the region, but they also pose a significant threat to local infrastructure and populations due to flooding caused by glacial lake outbursts. Currently, a limited amount of research has focused on the monitoring and analysis of glacial lakes in southeastern Tibet. Using Google Earth Engine (GEE) data in conjunction with meteorological data, this study examined the variation characteristics of glacial lakes in southeastern Tibet from 1993 to 2023. The region is subjected to segmentation and extraction of glacial lake boundaries via the FCN model. According to research findings, by 2023, southeastern Tibet is projected to contain 3,877 glacial lakes, encompassing an area of approximately 395.74 ± 22.72 km2. The distribution of glacial lakes in this region follows a pattern characterized by a relatively high concentration in the southern region and a relatively low concentration in the northern region. The glacial lakes with areas less than 0.1 km2 accounted for 94.24%, whereas those exceeding 3.0 km2 experienced the least amount of change. The analysis of regional elevation using the natural segmentation method reveals that glacial lakes are predominantly distributed within the altitude range of 4442 ~ 4909 m. The fluctuations in the annual mean precipitation and average annual temperature in the study area have decreased since 2008, while the growth trajectories of both the area and number of glacial lakes have gradually stabilized. However, given the backdrop of a slight increase in precipitation and a gradual increase in temperature, the proliferation of glacial lakes is projected to accelerate predominantly in Nyingchi City’s eastern and western regions. [ABSTRACT FROM AUTHOR]

Supraglacial debris cover considerably influences sub-debris ablation patterns and the surface morphology of glaciers by modulating the land–atmosphere energy exchange. Understanding its spatial distribution and temporal variations is crucial for analyzing melting processes and managing downstream disaster mitigation efforts. In recent years, the overall slightly positive mass balance or stable state of eastern Pamir glaciers has been referred to as the "Pamir-Karakoram anomaly". It is important to note that spatial heterogeneity in glacier change has drawn widespread research attention. However, research on the spatiotemporal changes in the debris cover in this region is completely nonexistent, which has led to an inadequate understanding of debris-covered glacier variations. To address this research gap, this study employed Landsat remote sensing images within the Google Earth Engine platform, leveraging the Random Forest algorithm to classify the supraglacial debris cover. The classification algorithm integrates spectral features from Landsat images and derived indices (NDVI, NDSI, NDWI, and BAND RATIO), supplemented by auxiliary factors such as slope and aspect. By extracting the supraglacial debris cover from 1994 to 2024, this study systematically analyzed the spatiotemporal variations and investigated the underlying drivers of debris cover changes from the perspective of mass conservation. By 2024, the area of supraglacial debris in eastern Pamir reached 258.08 ± 20.65 km2, accounting for 18.5 ± 1.55% of the total glacier area. It was observed that the Kungey Mountain region demonstrated the largest debris cover rate. Between 1994 and 2024, while the total glacier area decreased by −2.57 ± 0.70%, the debris-covered areas expanded upward at a rate of +1.64 ± 0.10% yr−1. The expansion of debris cover is driven by several factors in the context of global warming. The rising temperature resulted in permafrost degradation, slope destabilization, and intensified weathering on supply slopes, thereby augmenting the debris supply. Additionally, the steep supply slope in the study area facilitates the rapid deposition of collapsed debris onto glacier surfaces, with frequent avalanche events accelerating the mobilization of rock fragments. [ABSTRACT FROM AUTHOR]

Floods have catastrophic effects worldwide, particularly in monsoonal Asia. This systematic review investigates the literature from the past two decades, focusing on the use of remote sensing (RS), Geographic Information Systems (GISs), and technologies for flood disaster management in South Asia, and addresses the urgent need for effective strategies in the face of escalating flood disasters. This study emphasizes the importance of tailored GIS- and RS-based flood disaster studies inspired by diverse research, particularly in India, Pakistan, Bangladesh, Sri Lanka, Nepal, Bhutan, Afghanistan, and the Maldives. Our dataset comprises 94 research articles from Google Scholar, Scopus, and ScienceDirect. The analysis revealed an upward trend after 2014, with a peak in 2023 for publications on flood-related topics, primarily within the scope of RS and GIS, flood-risk monitoring, and flood-risk assessment. Keyword analysis using VOSviewer revealed that out of 6402, the most used keyword was "climate change", with 360 occurrences. Bibliometric analysis shows that 1104 authors from 52 countries meet the five minimum document requirements. Indian and Pakistani researchers published the most number of papers, whereas Elsevier, Springer, and MDPI were the three largest publishers. Thematic analysis has identified several major research areas, including flood risk assessment, flood monitoring, early flood warning, RS and GIS, hydrological modeling, and urban planning. RS and GIS technologies have been shown to have transformative effects on early detection, accurate mapping, vulnerability assessment, decision support, community engagement, and cross-border collaboration. Future research directions include integrating advanced technologies, fine-tuning spatial resolution, multisensor data fusion, social–environmental integration, climate change adaptation strategies, community-centric early warning systems, policy integration, ethics and privacy protocols, and capacity-building initiatives. This systematic review provides extensive knowledge and offers valuable insights to help researchers, policymakers, practitioners, and communities address the intricate problems of flood management in the dynamic landscapes of South Asia. [ABSTRACT FROM AUTHOR]

Dam breach can trigger severe flood disasters, threatening life and property safety, and having long-term impacts on the environment, society, and the economy. Dam breach floods also contaminate water bodies, degrading water quality and its sustainability. This study analyzes the characteristics and trends of dam breach research using research findings included in the CNKI (China National Knowledge Infrastructure, Beijing, China) database and the Web of Science (WoS) core database. Bibliometric methods, including word frequency analysis, co-citation analysis, and clustering analysis, were applied to the retrieved data. Using the CiteSpace (v6.3.R2) visualization tool, the study conducted statistical analyses and generated maps for publication trends, research institutions, and research hotspots. The findings indicate the following. (1) From 2000 to 2023, the number of research outcomes has been continuously growing both domestically and internationally with significantly more foreign-language publications than Chinese ones. (2) Chinese research institutions, notably the Chinese Academy of Sciences and the Nanjing Hydraulic Research Institute, have substantial international influence. (3) In terms of research hotspots, Chinese studies focus on the failure mechanisms of earth-rock dams, while foreign studies emphasize dam breach flood flows. (4) Establishing numerical models has emerged as a common trend in both Chinese and foreign research. These insights help identify deficiencies in current methods and technologies, allowing for the proposal of more scientific strategies for dam safety assessment. Based on these conclusions, some insights are proposed with the aim of reducing the risk of dam breaches, ensuring sustainable water resource management and utilization, promoting environmental protection, and fostering harmonious socio-economic development. [ABSTRACT FROM AUTHOR]

Temperate glaciers in the Kangri Karpo region of the southeastern Qinghai–Tibet Plateau (QTP) have experienced significant ablation in recent decades, increasing the risk of glacier-related hazards and impacting regional water resources. However, the spatial and temporal pattern of mass loss in these glaciers remains inadequately quantified. In this study, we used ASTER L1A stereo images to construct a high-resolution elevation time series and provide a comprehensive spatial–temporal assessment of glacier elevation change from 2000 to 2024. The results indicate that almost all glaciers have experienced rapid ablation, with an average surface elevation decrease of −18.35 ± 5.13 m, corresponding to a rate of −0.76 ± 0.21 m yr−1. Glaciers in the region were divided into the northern and southern basins, with average rates of −0.79 ± 0.17 m yr−1 and −0.72 ± 0.13 m yr−1, respectively. A notable difference in acceleration trends between the two basins was observed, with the elevation rate increasing from −0.78 ± 0.17m yr−1 to −1.04 ± 0.17 m yr−1 and from −0.52 ± 0.13 m yr−1 to −0.92 ± 0.13 m yr−1, respectively. The seasonal cycle was identified in glacier surface elevation change, with an accumulation period from November to March followed by a prolonged ablation period. The seasonal amplitude decreased with elevation, with higher elevations exhibiting longer accumulation periods and less ablation. Correlation analysis with meteorological data indicated that higher summer temperatures and increased summer rainfall intensify elevation loss, while increased spring snowfall may reduce ablation. Our analysis highlights distinct variations in glacier elevation changes across different locations, elevations, and climatic conditions in the Kangri Karpo region, providing valuable insights into glacier responses to environmental changes on the Tibetan Plateau. [ABSTRACT FROM AUTHOR]

In this research, a numerical model for simulating dam break floods was developed utilizing ArcGIS 10.8, 3ds Max 2021, and Flow-3D v11.2 software, with the aim of accurately representing the dam break disaster at Tianchi Lake in Changbai Mountain. The study involved the construction of a Triangulated Irregular Network (TIN) terrain surface and the application of 3ds Max 2021 to enhance the precision of the three-dimensional terrain data, thereby optimizing the depiction of the region's topography. The finite volume method, along with multi-block grid technology, was employed to model the dam break scenario at Tianchi Lake. To evaluate the severity of the dam break disaster, the research integrated land use classifications within the study area with the simulated flood depths resulting from the dam break, applying the natural breaks method for hazard level classification. The findings indicated that the computational fluid dynamics (CFD) numerical model developed in this study significantly enhanced both the efficiency and accuracy of the simulations. Furthermore, the disaster assessment methodology that incorporated land use types facilitated the generation of inundation maps and disaster zoning maps across two scenarios, thereby effectively assessing the impacts of the disaster under varying conditions. [ABSTRACT FROM AUTHOR]

Supraglacial debris modulates the thermal regime and alters glacial melt rates depending on its thickness. Thus, the estimation of debris thickness becomes imperative for predicting the hydrological response and dynamics of such glaciers. This study tests the performance of empirical and thermal resistance-based debris thickness approaches against field measurements on the Hoksar Glacier, Kashmir Himalaya. The aim of this study was accomplished using thermal imageries (Landsat 8 Operational Land Imager [Landsat-OLI], 2017 and Advanced Spaceborne Thermal Emission and Reflection Radiometer [ASTER] Surface Kinetic Temperature Product [AST08], 2017) and the European Centre for Medium-Range Weather Forecasts (ECMWF) Reanalysis v5 (ERA-5) datasets. First, the spatially resolved estimates of debris thickness for the entire debris-covered zone were achieved by establishing an empirical relationship between debris thickness and debris surface temperature (both field and satellite thermal imageries). Second, debris thickness for every pixel of thermal imagery was executed by calculating thermal resistance from the energy balance model incorporating primary inputs from (ERA-5), debris temperature (AST08, Landsat OLI), and thermal conductivity. On comparison with field temperature and thickness measurements with satellite temperature, homogenous debris thickness pixels showed an excellent coherence (r = 0.9; p < 0.001 for TAST08 and r = 0.88; p < 0.001 for TLandsat OLI for temperature) and (r = 0.9; p < 0.001 for TAST08 and r = 0.87; p < 0.002 for TLandsat OLI for debris thickness). Both approaches effectively captured the spatial pattern of debris thickness using Landsat OLI and AST08 datasets. However, results specify an average debris thickness of 18.9 ± 7.9 cm from the field, which the empirical approach underestimated by 12% for AST08 and 28% for Landsat OLI, and the thermal resistance approach overestimated by 6.2% for AST08 and 5.1% for Landsat OLI, respectively. Debris thickness estimates from the thermal resistance approach (deviation 11.2% for AST08 and 11.6% for Landsat OLI) closely mirror the field measurements compared to the empirical approach (deviation 26.9% for AST08 and 35% for Landsat OLI). Thus, the thermal resistance approach can solve spatial variability in debris thickness on different heavily debris-covered glaciers globally without adequate knowledge of field measurements. [ABSTRACT FROM AUTHOR]