Main Glacier Research Articles

Recent ice‐contact delta formation in front of Pio XI glacier controls sedimentary processes in Eyre Fjord, Patagonia

AbstractPio XI Glacier (49°S) is the largest and one of the very few advancing glaciers in Patagonia. Satellite data indicate that the main glacier terminus transitioned from calving to land‐based around 2010, effectively resulting in the formation of an ice‐contact delta at the head of Eyre Fjord. Here, we investigate how this ice‐contact delta formation affected sediment transport processes in Eyre Fjord. Sediment cores and seismic profiles collected along the fjord provide evidence for a relatively abrupt increase in the number and magnitude of turbidity currents, coeval with the formation of the ice‐contact delta. This observation is supported by modern summer hydrographic observations and bathymetric data. We posit that the ice‐contact delta formation resulted in sediment input being concentrated at specific subaerial locations across the fjord head, which favoured the development of plume‐triggered turbidity currents. This suggests that a sudden increase in turbidite thickness in fjord sediment records could represent ice‐contact delta development at fjord heads.

Inferring glacier mass balance from Sentinel-1 derived ice thickness changes using geoinformatics: A case study of Gangotri glacier, Uttarakhand, India

All glaciers respond to climatic changes by fluctuating their mass. Investigations of glacier dynamics are necessary for glacier monitoring. Himalayan glaciers make ongoing glacier observations challenging due to their location in a severe topographic environment and inhospitable terrain. Glacier area contraction or extension, together with a corresponding snout shift, can be linked to oscillations in glacier mass. Sentinel-1 dual-polarized datasets were used in this investigation to retrieve glacier surface velocity. Estimates of ice thickness were enhanced by segmenting the glacier into 100-m height intervals. Also, ice thickness variations between 2017 and 2022 have been used to compute glacier mass balance, and the results for several glacier zones have been briefly analyzed. The study revealed that the maximum surface velocity above Gangotri Glacier was approximately 0.33 m/day, with an estimated average of 0.09 m/day. Surface velocities of the central trunk have been seen to range from 0.12 m/day to 0.23 m/day. Additionally, between 2017 and 2022, the surface velocity was spotted between 0.19 m/day to 0.35 m/day. For the glacier, an average ice thickness of 189 ± 17.01 m was calculated. In the central parts, where the drag was least noticeable, thicknesses up to 587 ± 52.83 m were estimated. In the lower accumulation zone and middle reaches, the thickness was found to be decreasing between 2017 and 2022, which can be attributed to increased melting and glacier slowdown. Due to the increased glacier movement throughout time, the lower accumulation reaches over the main glacier body, and its tributaries have experienced mass balancing rates ranging from −1.3 m.w.e./year to −0.5 m.w.e./year (thickness change between −3 m/year and −0.6 m/year). With the help of previous research and existing data, the results were compared and validated. The suggested algorithm and findings can serve as inputs for satellite-based ice thickness measurements and as fundamental research for the forthcoming NISAR mission (expected by mid-2024) which will carry L- and S-band antennas.

Mapping of morainic complexes and reconstruction of glacier dynamics north-east of Cook Ice Cap, Kerguelen Archipelago (49°S)

AbstractDue to the limited landmasses in the Southern Hemisphere, we must rely on data from sub-Antarctic islands within the Southern Ocean to record historical climate patterns. Over the past few decades, glaciers throughout the Southern Ocean region have experienced a noticeable retreat, especially in the Kerguelen Archipelago, whose glacial landforms offer valuable insights into long-term climate fluctuations. Our comprehensive glacial geomorphological study conducted in its remote north-western region meticulously examines morainic complexes from smaller cirque glaciers and larger outlet glaciers stemming from the Cook Ice Cap. We mapped these landforms to reconstruct historical glacier extents during the Holocene. The surface area of the three main glaciers had decreased in 1962–1964 by only 35% compared to their maximum extents, whereas surface area changes across 12 time intervals spanning from 1962 to 2019 from aerial and satellite imagery reveal a cumulative reduction of 43.5%. Additionally, we modelled changes in glacier thickness and equilibrium-line altitude for the key glaciers at three distinct stages: 1) their maximum extent before 1962, 2) the early 1960s and 3) 2019. This multifaceted analysis contributes valuable insights into the dynamics of Kerguelen's glaciers and the broader implications for understanding past and ongoing climate dynamics in the Southern Hemisphere.

Gangotri glacier dynamics from multi-sensor SAR and optical data

The present study has analyzed dynamics of Gangotri glacier using multiple remote sensing (RS) datasets and ground based observations. Interferometric Synthetic Aperture Radar (InSAR) data pairs from European Remote Sensing satellite (ERS 1/2) tandem pair for spring of 1996, Sentinel-1 SAR pairs and Japanese’s Advance Land Observation System (ALOS) PALSAR-2 SAR data for Spring of 2015 were used to derive glacier-surface velocity at seasonal time scale using Differential InSAR (DInSAR) techniques. Bi-static TanDEM-X (Experimental) data was used for the 1st time to estimate glacier surface elevation changes for a period of 22, 44, 88 days during summer of 2012 using InSAR techniques in this study. Annual glacier velocity was also estimated using temporal panchromatic data of LANDSAT-5 (30 m), LANDSAT-7/8 (15 m), Sentinel-2 (10 m) and Indian Remote Sensing Satellite IRS-1C/1D panchromatic (5 m) data during 1998–2019 with feature tracking approach. This study has estimated glacier surface velocity and surface elevation changes for the major parts of Gangotri glacier and its tributary glaciers using medium to high resolution optical and SAR datasets, at annual and seasonal time scale, which is an improvement over earlier studies, wherein snout based glacier recession or only main glacier velocities were reported. The velocity and slope were used to assess glacier-ice thickness distribution using Glabtop-2, slope dependent and laminar flow based methods over the Gangotri group of glaciers. The estimated ice thickness was estimated in the range of 58–550 m for the complete glacier while few small areas in middle & upper regions carry higher thickness of about 607 m. The estimated glacier-ice thickness was found in the range of 58–67 m at the snout region. The estimation was validated using 2014 field measurements from Terrestrial Laser Scanner (TLS) for the first time and correlation was found to be 0.799 at snout of the glacier.

Energy mass balance and flow modeling of early Holocene glaciers in the Queshque valley, Cordillera Blanca, Peru

Our limited knowledge of the timing and pattern of early Holocene climate variability in the tropical Andes hinders our ability to evaluate any potential linkages between low and high latitude oceanic-atmospheric dynamics. There is mounting evidence that glaciers in the Peruvian Andes stabilized at times during the early Holocene, suggesting there were periods of colder and/or wetter conditions that interrupted an overall pattern of a warmer and drier climate. Evaluating the global significance of these glacial fluctuations requires that the nature of these apparent cooling events and any shifts in the hydrologic cycle be better quantified. Here we apply a physically-based glacier model to reconstruct and interpret early Holocene-aged paleoglaciers in steady-state with a range of tropical climatic conditions in the Queshque valley of the Cordillera Blanca, Peru (9.8°S). This model uses a LiDAR-based digital elevation model (DEM) and hourly meteorological data as inputs to calculate the fully-distributed surface energy and mass balance (SEMB). This approach allows us to better capture the diurnal range of environmental variability at a spatial resolution that has not been achieved with previous paleo-glacier modeling efforts in this region. A 3-D rendition of paleoglaciers was then developed based on a flow model that responds to the SEMB input, accounting for the valley topography. The model was validated by simulating glaciers that match both field and satellite observations of modern glacier area limits, as well as ice thicknesses that are consistent with recently measured ground-penetrating radar (GPR) profiles of the main glacier tongue. After adjusting for changes in early Holocene global radiation values, and using regional paleoclimate records as constraints for the model, the maximum early Holocene ice limit in the valley dating to ∼10.8 (±0.1) ka was reconstructed using a 3.0 °C cooling and a 25% increase in precipitation relative to today. An up-valley ice extent dating to ∼9.4 (±0.3) ka was reconstructed using a 2.8 °C cooling and no change in precipitation amounts relative to today. These results suggest that conditions were cold and wet enough to maintain glaciers at times during the early Holocene, even though a shift to drier conditions combined with modestly warmer temperatures drove a phase of ice retreat from at least ∼10.8 to ∼9.4 ka. These results suggest that southern tropical temperatures and the hydrologic cycle rapidly reorganized during the early Holocene in conjunction with diminishing ice sheets and shifting environmental conditions in the high latitudes.

Element Content in Volcano Ash, Soil and River Sediments of the Watershed in the Volcanic Area of South Iceland and Assessment of Their Mobility Potential

In this work, we present the results of element content in river sediments and soil of the Rangárvellir river in southern Iceland as well as in the volcano ash from the Eyjafjallajökull eruption in 2010. Severe natural catastrophes have devastating impact on the environment. We selected the Rangárvellir area located in the vicinity of Mt Hekla, Iceland’s most active volcano, for our study. This study site is ideal to investigate wind and water erosion and sediment transport processes of two main glaciers rivers: the Eystri-Rangá and the Ytri-Rangá and the Hroarslækur River. Sediments of these rivers consist of volcano materials, ash and lava. In order to assess the sediment dynamics, we collected sediment, soil and volcanic ash. The fractioning of the elements was carried out using sequential extractions. The distribution of Si indicates that the sediments originate from the same geochemical basis. Li and partly B exist in the first phase of volcanic ash and river sediments but not in the mobile phases of soils. In the mobile phase of volcanic ash, P was found but it did not exist in the first phase of soil and sediments. These results suggest the different chemical fingerprints in the water sediments and surrounding soil.

Glacimarine sediment flows in small bays on the Danco Coast, Antarctic Peninsula

Global atmospheric warming and rising ocean temperatures can contribute to the acceleration of glacier melting and influence the generation and physical characteristics of sediment flows in bays and fjords of the Antarctic Peninsula. During the First Scientific Expedition of Colombia to the Antarctic, carried out between January and February 2015, hydrographic variables (temperature, salinity, pressure and turbidity) were measured in the water column, from very close to the main glacier front towards the offshore, on 5 bays of the Danco Coast, Western Antarctic Peninsula. Glacimarine sediment plumes from the tidewater glacier were identified in all bays, however, with varying spatial extensions as well as the concentration of sediments, being those of the central area of the Danco Coast, the most extensive and concentrated. By comparison with previous years, in this work higher average particle concentrations were recorded. The greater flow of glaciomarine sediments could be associated with greater glacial melting, among other possible factors

Anomalous glacier thinning due to climate feedback mechanism in the Himalaya and evidences in other mountain ranges

The heterogeneous ice-melt of glaciers in the Himalaya and other mountain ranges is often associated with debris cover, slope, precipitation, and temperature. However, this study ascertains that the climate feedback mechanism introduced due to meltwater influx of retreating tributary glaciers accelerates the melting of the main glacier body. Such regions have shown high elevation change at the surface, leading to a higher ice-mass loss. The point locations of meltwater influx are identified, and a relationship is presented between the density of meltwater influx points and glacier thinning. The existing mass balance models do not account for this process, thereby underestimating the current and the future mass loss. It is recommended that future mass loss prediction/projection models should consider the influence of the climate feedback system.

Geomorphology and surface geology of Mount St. Helens volcano

ABSTRACT Mount St. Helens is a stratovolcano of the Cascadia volcanic arc well known worldwide for its volcanic collapse and eruption in 1980, which caused considerable destruction and changed the geomorphology of the volcano and of a considerable portion of its surroundings. This paper presents a geomorphology and surface-geology map of both the wider Mount St. Helens, Washington (USA), at the 1:50,000 scale, and of its crater, at the 1:25,000 scale. The map is obtained from the interpretation of two high-resolution, air-borne acquired, digital terrain models, LiDAR dataset, combined with Google Earth imaging, geological information and field surveys. The geomorphology of the area is largely dominated by landforms connected with the blast of 1980 and the dome extrusion of 2004, which also affected the shape of the main glacier in the crater.

Deglacierization of a Marginal Basin and Implications for Outburst Floods, Mendenhall Glacier, Alaska

Suicide Basin is a partly glacierized marginal basin of Mendenhall Glacier, Alaska, that has released glacier lake outburst floods (GLOFs) annually since 2011. The floods cause inundation and erosion in the Mendenhall Valley, impacting homes and other infrastructure. Here, we utilize in-situ and remote sensing data to assess the recent evolution and current state of Suicide Basin. We focus on the 2018 and 2019 melt seasons, during which we collected most of our data, partly using unmanned aerial vehicles (UAVs). To provide longer-term context, we analyze DEMs collected since 2006 and model glacier surface mass balance over the 2006-2019 period. During the 2018 and 2019 outburst flood events, Suicide Basin released 30 million m3 of water within approximately 4 to 5 days. Since lake drainage was partial in both years, these 30 million m3 represent only a fraction (60%) of the basin's total storage capacity. In contrast to previous years, subglacial drainage was preceded by supraglacial outflow over the ice dam, which lasted ~1 day in 2018 and 6 days in 2019. Two large calving events occurred in 2018 and 2019, with submerged ice breaking off the main glacier during lake filling, thereby increasing the basin's storage capacity. In 2018, the floating ice in the basin was 36 m thick on average. In 2019, ice thickness was 29 m, suggesting rapid decay of the ice tongue despite increasing ice inflow from Mendenhall Glacier. The ice dam at the basin entrance thinned by more than 5 m per year from 2018 to 2019, which is approximately double the rate of the reference period 2006-2018. While ice dam thinning reduces water storage capacity in the basin, that capacity is increased by declining ice volume in the basin and longitudinal lake expansion, with the latter process challenging to predict. The potential for premature drainage onset, intermittent drainage decelerations, and early drainage termination further complicates prediction of future GLOF events.

Discovering anomalous dynamics and disintegrating behaviour in glaciers of Chandra-Bhaga sub-basins, part of Western Himalaya using DInSAR

Glacier velocity is one of the important parameters to know about glacier dynamics, its mass and health. Understanding glacier velocity also assists in the analysis of ice thickness, ice flux and mass balance. Furthermore, basin/sub-basin wise studies are helpful to understand the climate change over that region instead of monitoring individual glaciers. In the current study, the spatial distribution of glacier velocity is generated for the entire Chandra and Bhaga sub-basins, in the Lahaul-Spiti district of Himachal Pradesh, India, using Advanced Land Observing Satellite-2/Phased Array type L-band Synthetic Aperture Radar-2 (ALOS-2/PALSAR-2) differential interferometry pair images with a 14-days temporal gap. The glaciers in Chandra sub-basin are found to have a high flow rate as compared to the glaciers in Bhaga sub-basin. Local slope and ice thickness, which decrease towards the terminus in general, control the movement of valley glaciers, and lower movement rate is observed for most of glaciers towards the terminus/frontal area. However, a few glaciers of Bhaga sub-basin demonstrate an accelerated movement in their frontal areas. This irregular behaviour is also studied in this work and it is discovered that terrain slope and influx of melting water from adjacent glaciers are the major causes for such behaviour of these glaciers. They are, therefore, prone to accelerated mass loss compared to other glaciers in the sub-basin. Another key finding of the anomalous glacier dynamics study is the disintegrating behaviour of glaciers, which is also identified by interpreting the responses of physical scattering mechanisms retrieved from glaciers using fully polarimetric ALOS-2/PALSAR-2. Warming temperatures are expected to cause glacier retreat and separation of tributary glaciers from the main glacier body. Melt water from tributary glaciers can further accelerate glacier flow and ice melt in lower part of glacier trunk. This can lead to formation of dead ice zones and disintegration of Himalayan glaciers, which are supported by numerous tributary glaciers. Therefore, we expect that the loss in glacier area due to warming will be larger than the present prediction, where mass loss is considered from conventional way.

Depositional setting of the southern arms of Lago Argentino (southern Patagonia)

ABSTRACT Lago Argentino hosts a series of calving glaciers originating from the Southern Patagonian Icefield, the largest temperate ice cap of the southern hemisphere. Brazo Rico and Brazo Sur are two basins located in the southern part of Lago Argentino, where a series of high-resolution seismic profiles have allowed reconstruction of its depositional setting and sedimentary architecture, and to produce the following maps: top of the acoustic basement, top of the glacial sequence, and thickness of the glacio-lacustrine deposits. Data reveal the role of basement highs in the complex dynamic behavior of the two main glaciers, Perito Moreno and Frías glaciers, which fluctuated along Brazo Rico and Brazo Sur since the end of the Last Glacial Maximum. Their advances and retreats are testified by the presence of several moraine fronts buried beneath a generally undisturbed, glacio-lacustrine and lacustrine sequence, which records the depositional history of the southern arms of Lago Argentino.

Дистанционное и георадарное исследование ледника Радде хребта Мунку-Сардык (Восточный Саян)

The Munku-Sardyk (Eastern Sayan) glacier has been described and studied for more than 100 years. The first largest glacier of Peretolchina was studied in the most detailed detail. Radde's second-largest glacier is much weaker. Monitoring of surface characteristics of the Radde glacier by ground methods and using data of remote sensing of the Earth (RSE) has been carried out since 2006. In 2018, georadar profiling of this glacier was performed for the first time. As a result, it was possible not only to clarify its surface characteristics, but also to assess the power of the ice and the internal structure (a layer of firn, ice, bed). According to the RSE, its geometric changes have been revealed. Over 120 years, the open part of the Radde Glacier has shrunk from 0.4 to 0.09 km2, and the length from 1 to 0.4 km. It also revealed the division of the glacier into two parts and the intensive reservation of the bottom of the main part of the tongue by surface moraines and the formation of a glacial lake on the glacier itself in the lower part of the second half. Radar research using the Oko-2 georadar, allowed to determine the volume of ice of this glacier 0.003 km3 and the greatest thickness of the main ice body 42 m. The main glacier flows down from the Eskadriliy top, 3168 m, to the north, flows on the cross-bar and from it turns to the northeast, and at the bottom of the kar will continue to flow north again.

Estimación de la temperatura basal del “Glaciar Norte” del volcán Citlaltépetl, México. Modelo para determinar la presencia de permafrost subglaciar

Se estudian las condiciones de temperatura y la conductividad del hielo del “Glaciar Norte” del volcán Citlaltépetl con el objeto de determinar la existencia de permafrost basal. A partir de registros de temperatura cercanos a la superficie se estimó la temperatura media en estado estacionario del interior del “Glaciar Norte” mediante un método sinusoidal que utiliza las propiedades termo-conductoras del hielo. A través de su perfil de temperatura se obtuvo una aproximación a las condiciones térmicas del principal glaciar de México. Los resultados podrían sugerir la existencia de un permafrost basal, el cual sería producto del aislamiento del hielo y de la conducción térmica por contacto directo entre el hielo y el substrato.

Spatio-temporal and surface elevation change assessment of glaciers of Sikkim Himalaya (India) across different size classes using geospatial techniques

An assessment of the influence and significance of different topographic and morphometric parameters of glacier catchments such as size, average slope, median elevation, and aspect upon the spatio-temporally changing characteristics of glaciers belonging to different size classes in Tista river basin of Sikkim Himalaya has been performed. The reference years of 2000 and 2018 were considered and different morphometric techniques showed recessive nature and shape change of the observed main glaciers along with some of the tributary glaciers. Pearson’s correlation coefficient and Student’s t test were applied to measure the correlation and statistical significance of used parameters to understand the varying morphometric and topographic conditions of the glaciers. LANDSAT TM (thematic mapper), LANDSAT 7 ETM + (enhanced thematic mapper), and LANDSAT 8 (OLI) (operational land imager) imageries and shuttle radar topographic mission (SRTM) digital elevation model (DEM) and different automated and semi-automated techniques indicated overall loss of 19.78% over the years 2000 to 2018 of the glaciated area investigated and such decrease in respective years of reference was 2.06% for the year 2000 and 1.65% for the year 2018, respectively, of the total geographic area of Sikkim. TanDem-X DEM (90 m) was useful in inferring glacier surface elevation change.

Supraglacial ice cliffs and ponds on debris-covered glaciers: spatio-temporal distribution and characteristics

ABSTRACTIce cliffs and ponds on debris-covered glaciers have received increased attention due to their role in amplifying local melt. However, very few studies have looked at these features on the catchment scale to determine their patterns and changes in space and time. We have compiled a detailed inventory of cliffs and ponds in the Langtang catchment, central Himalaya, from six high-resolution satellite orthoimages and DEMs between 2006 and 2015, and a historic orthophoto from 1974. Cliffs cover between 1.4% (± 0.4%) in the dry and 3.4% (± 0.9%) in the wet seasons and ponds between 0.6% (± 0.1%) and 1.6% (± 0.3%) of the total debris-covered tongues. We find large variations between seasons, as cliffs and ponds tend to grow in the wetter monsoon period, but there is no obvious trend in total area over the study period. The inventory further shows that cliffs are predominately north-facing irrespective of the glacier flow direction. Both cliffs and ponds appear in higher densities several hundred metres from the terminus in areas where tributaries reach the main glacier tongue. On the largest glacier in the catchment ~10% of all cliffs and ponds persisted over nearly a decade.

SNOW COVER AND GLACIER DYNAMICS STUDY USING C-AND L-BAND SAR DATASETS IN PARTS OF NORTH WEST HIMALAYA

Abstract. The seasonal snow cover and permanent ice in form of Himalayan glaciers provide fresh water to many perineal rivers of Himalayas. The melt water from seasonal snow and glaciers, especially during of 15 March to 15 June acts as important source of water for drinking, hydropower and irrigation requirements of many areas in North India. This work has highlights the use of C-band Synthetic Aperture Radar (SAR) data from RISAT-1, Sentinel-1A and 1B satellites and ALOS-PALSAR-2 PolInSAR data for snow cover and glacier dynamics study for parts of North West Himalaya. Glacier velocity was derived using InSAR based method using 6 day temporal interval images from Sentinel-1 satellites and 14 day interval for PALSAR-2 satellite. High coherence was obtained for main glacier in both the data sets, which resulted accurate line of site (LOS) glacier velocity estimates for test glaciers. These InSAR data glacier velocity results are obtained after a gap of 21 years. Glacier facies was estimated using multi-temporal SAR image composition based classification. All these maps were verified by extensive ground surveys done at these sites during 2014–2017. The time series data of C-band SAR in VV/VH polarisation was also used to map snow cover in test basins of Bhagirathi and Beas River. The VV/VH data clearly shows difference between dry and wet snow, thus helping in improved snow cover mapping using SAR data. This study will help in refining algorithms to be used for such studies using upcoming NASA-ISRO SAR (NISAR) mission.

Ice discharge error estimates using different cross-sectional area approaches: a case study for the Canadian High Arctic, 2016/17

ABSTRACTWe analyse the various error sources in the estimation of ice discharge through flux gates, distinguishing the cases with ice-thickness data available for glacier cross-sections or only along the centreline. For the latter, we analyse the performance of three U-shaped cross-sectional approaches. We apply this methodology to glaciers of the Canadian High Arctic. The velocity field is the main error source for small and medium-size glaciers (discharge <100 Mt a−1) with low velocities (<100 m a−1), while for large glaciers (discharge >100 Mt a−1) with high velocities (>100 m a−1) the error in cross-sectional area dominates. Thinning/thickening between ice-thickness and velocity measurements should be considered, as it implies systematic errors up to 8% in our study. The U-shaped parabolic approach, which allows for an adjusted estimation when the ice-thickness measurement point is displaced from the glacier centreline, performs best, with small bias and admissible standard error. We observe an increase of ice discharge from the main glaciers (Trinity and Wykeham) of the Prince of Wales Icefield from 2015 to 2016, by 5 and 20%, respectively, followed by a decrease in 2017, by 10 and 15%, respectively. Belcher Glacier, of the Devon Ice Cap, maintains similar discharges during 2015–17.

MEASURING SURFACE DEFORMATION IN GLACIER RETREATED AREAS BASED ON PS-INSAR – GELADANDONG GLACIER AS A CASE STUDY

Abstract. Glaciers are retreating in many parts of the world as a result of global warming. Many researchers consider Qinghai-Tibetan Plateau as a reference for climate change by measuring glaciers retreat on the plateau. This retreat resulted in some topographic changes in retreated areas, and in some cases can lead to geohazards as landslides, and rock avalanches, which is known in glacier retreated areas as paraglacial slope failure (PSF). In this study, Geladandong biggest and main glacier mass was selected to estimate surface deformation on its glacier retreated areas and define potential future PSF based on PS-InSAR technique. 56 ascending and 49 descending images were used to fulfill this aim. Geladandong glacier retreated areas were defined based on the maximum extent of the glacier in the little ice age. Results revealed a general uplift in the glacier retreated areas with velocity less than 5mm/year. Obvious surface motion was revealed in seven parts surround glacier retreated areas with high relative velocity reached ±60mm/year in some parts. Four parts were considered as PSF potential motion, and two of them showed potential damage for the main road in the study area in case of rock avalanche into recent glacier lakes that could result in glacier lake outburst flooding heading directly to the road. Finally, further analysis and field investigations are needed to define the main reasons for different types of deformation and estimate future risks of these types of surface motion in the Qinghai-Tibetan Plateau.

Surge of Hispar Glacier, Pakistan, between 2013 and 2017 detected from remote sensing observations

This study analyses the behaviour of an actively surging glacier, Hispar, in Pakistan using remote sensing methods. We used 15m panchromatic band of Landsat 8 OLI from 2013 to 2017 to assess the changes in glacier velocity, glacier geomorphology and supraglacial water bodies. For the velocity estimation, correlation image analysis (CIAS) was used, which is based on normalized cross-correlation (NCC) of satellite data. On-screen digitization was employed to quantify changes in the glacier geomorphology and dynamics of supraglacial water bodies on the glacier. Our velocity estimates indicate that the upper part of the glacier is presently undergoing an active surge which not only affects the debris distribution but also impacts the development of supraglacial water bodies. Velocities in the actively surging part of the main glacier trunk and its three tributaries reach up to ~900myr−1. The surge of Hispar also impacts the distribution of supraglacial debris causing folding of the medial moraines features present on the glacier surface. Changes in the number and size of supraglacial lakes and ponds were also observed during the observation period from 2013 to 2017.