Landscapes: PIndari Glacier Trail

Every time I am dragging myself back on the last day of a tiring trek in the Himalaya, I curse and swear that I’ll never do this again. And yet, here I am, exploring the Pindari Glacier area in the Kumaon. What a beauty!!

The trail begins at village Khati. This is also the starting point for the trek to Sunderdunga Glacier which I managed to do last year. A third trail to Kafni Glacier also starts here. Landslides has made a section of that trail inaccessible for the time being.  Pindari Glacier was a favorite recreation site for colonial administrators during the Raj. As a result, two comfortable guest houses were built along the trail. The first one is at Dwali, a 12 km walk from Khati. The next hut is a further 7 km walk at Phurkiya. A cot and a warm meal is available at both places. The caretaker lives there from April to late November. 

My preference has been to go to these Uttarakhand trails in early mid November. I love that season with its cold weather, clear views, and the occasional snow flurry. And the last day walk from Phurkiya camp to the glacier is breathtaking (it was 6 below zero when we started!!).

Here are some pics of the landscapes along the trail. 

A walk through the forest with a peek of the snow ridges.

Splashes of  yellow in a steep valley.

River terraces.  

T0 is the old river bed. It is now colonized by vegetation. The river then incised or cut down into the sediment creating a bench or a terrace clinging to the valley side. There was a second phase of sediment accumulating on the new river bed followed by another incision, creating the T1 terrace at a lower level. I love to observe these changing behavior of rivers as I walk along. 

Organic red pigments have colored these boulders in the Pindari river bed.  

Dwali campsite which you get to by crossing this rickety wooden bridge over a fast flowing river.  

Ahead of Phurkiya camp, walking towards the glacier, the valley widens, opening up some great views. 

Pindari Glacier, still about 3 km walk away.  

At "Zero Point", standing on a narrow lateral moraine!  

Listen to an afternoon rain shower in a High Himalaya valley, near Phurkiya campsite. 

Above the tree line. These glacial valleys are harsh, desolate, and beautiful.

 Until next time...

Shrinking Panchachuli Glacier

Over the past few years I have been regularly visiting the Panchachuli Glacier in the Kumaon Himalaya. Accompanying me are a group of geology enthusiasts from all walks of life. This is an outreach effort I have undertaken in collaboration with Deep Dive India. 

Every time I make it a point to walk to the glacier snout where the river Dhauliganga emerges from an ice cave. Every time my experience of approaching the glacial terminus is different. The Panchachuli Glacier is a shape shifter. I have to walk a little longer each time to reach the snout, negotiating the changing configuration of rubble mounds and streams.

I thought I would document the retreat of the snout over time using field photos from my visits beginning year 2017 and supplemented by Google Earth imagery going back to the year 2000. I won't keep you in suspense. The glacier snout has retreated by about 1 kilometer in the last 25 years. That is by 40 meters per year. But the rate has varied, with an acceleration in the past 8 years.

Let's begin with a synoptic view of the glacial valley.

 

The walk begins at village Dantu. It is about 6 kilometers to the present position of the snout. The red lines are edges of old lateral moraines. They are stable features and are easily recognizable in the satellite images. They are my fixed marker posts against which I will track the changing position of the snout. Distance to the snout in all images is estimated from marker post A. 

Year 2000- Google Earth Imagery.

Notice the curvilinear cracks (white arrow) near the snout. The glacier retreats by slices of ices cleaving off these cracks. Between the two marker posts is a smaller glacial valley. Semicircular depressions and ponds have formed on the glacier surface due to thawing of the ice. The distance to the snout from A is about 1.3 kilometers.

Year 2012- Google Earth Imagery.

Distance to the snout from marker post A is 840 meters indicating a retreat of 460 meters in 12 years, averaging about 38 meters per year. The smaller valley still has a fair amount of ice accumulation.   

Year 2017- Field Photo.

This was taken during my first visit from a high vantage point along the trail to "Zero Point", a popular trekking spot along an old lateral moraine. 

Year 2017- Google Earth Imagery.

Between 2012 and 2017, the snout has retreated a further 120 meters, an average retreat of about 26 meters per year. The frontal part of the smaller side glacier is now showing signs of collapse. Pronounced curvilinear cracks have appeared and glacier retreat has left behind rubble mounds producing an uneven topography at the front.

Year 2023- Field Photo.

Taken from close to the 2017 vantage point. 

Year 2023- Google Earth Imagery.

The snout is now just 280 meters from marker post A. This implies a retreat of about 430 meters between the years 2017 to 2023. The average rate of retreat is an astonishing 71 meters per year. There are signs of significant changes around the glacial terminus. The snout is now up-valley of marker post B. The smaller valley between the marker posts is almost completely ice free. A surface drainage has developed along this side valley and joins the main Dauliganga stream just downstream of the snout. The multiple small streams in the area is due to drainage finding its way around fresh mounds of rubble.

My most recent visit was earlier this month in May. Google Earth does not have imagery from 2025. But I will share a field photo taken from the high slopes looking down towards the snout.

 

The snout has retreated by tens of meters and is almost in line with marker post A, strongly suggestive of high rates of retreat persisting over the last couple of years. The area around the terminus is a degraded landscape with rubble heaps everywhere. We could not get very close to the ice cave this time due to time constraints but I assessed it would have been a more difficult passage negotiating the multiple streams and boulders. 

The rates of retreat that I have estimated are a little higher than those made by geologists from other parts of the Himalaya. A Ministry of Earth Sciences press release from 2023 has shared some data on Himalaya glaciers. The average retreat rate for Ganga Basin glaciers is about 15 meters per year, while that for Brahmaputra Basin is about 20 meters per year. 

A more detailed study of Gangotri, India's most famous glacier, shows a retreat rate of 20 meters per year. Significantly, the retreat accelerated in the past few years to about 33 meters per year, a pattern I too have observed for the Panchachuli Glacier. 

Himalayan rivers provide water security for hundreds of millions of people in the Indian subcontinent. Glacial runoff contributes a timely and significant amount of water to these rivers. The Indian government is building and planning scores of dams in the Indus, Ganga, and Brahmaputra basins with elaborate arrangements of water use and water sharing with different stakeholders. Given the massive ice loss and changing climatic patterns, it is imperative that detailed feasibility studies of these projects in terms of both safety, and near, mid, and long term projections of water availability are carried out. 

I'm putting up this final image taken in May 2025 from near the Dhauliganga stream looking towards the terminus. 

 

It captures nicely the long term changes that have taken place. The blue line marks the top of the glacier. Fresh collapse has exposed shiny ice walls. The brown line above is the crest of an old lateral moraine, several hundred feet higher than the present day glacier surface. 

Is there a better landscape to contemplate and appreciate climate change and the dynamic glaciers which have shaped our planet over past centuries?

Milam Glacier Trail - Landscapes

Earlier in the month from October 10th to October 18th, I walked the Milam Glacier trail in the Kumaon Himalaya, Uttarakhand. A four day walk through the Johar Valley from Lilam village near Munsiyari to Milam took me past some fantastic landscapes and geology. 

After an initial breathtaking climb which takes you from about 6000 feet at Lilam to more than 9,000 feet at a high ridge known as Mainsingh Top, the trail descends towards the Indo-Tibetan Border Police outpost at Bugdiyar. After this, a gradual ascent takes you higher, with the rest of the walk undulating between 10,000 to 11,000 feet ASL. I was lucky with the weather. After walking the first two days in belting bone chilling rain the skies cleared and I was treated to some gorgeous views of the High Himalaya. 

I am posting a few pictures of the landscapes along this scenic route. The pictures are roughly ordered from the start towards the end of the trail.

The Greater Himalaya near Bawaldhar, a small resting stop which we came across on the first day.

Another view of the Greater Himalaya in the vicinity of Bugdiyar. Notice the steep slopes, narrow valleys and the sheer rock faces and the cascading Goriganga river. 

A lovely rough trail near the Laspa area. The October colors really makes the landscape radiant. 

After Laspa, the Greater Himalaya made up of high grade metamorphic rocks give way to the low grade metamorphic and sedimentary terrain of the Tethyan Himalaya. You do notice a change in the topography from the sheer steep slopes and narrow valleys typical of the Greater Himalaya to the wider valley forms and gentler gradients of the Tethyan domain. 

The Goriganga at Rilkot. The river is more serene here making a soothing gurgling sound as it flow past. Also check out the gorgeous longitudinal gravel bars in the river channel. Permanent Link: Goriganga at Rilkot.  

The high meadows of Martoli. This is a beautiful if desolate place with stunning views of the high Himalayan all around. 

A lone resident of Burfu surveys his kingdom. Most of the villages were empty of people as residents had migrated to lower altitudes for the winter. The flat plateau seen in the background is a glacial outwash terrace. It was formed by streams redepositing debris that accumulates in front of a glacier. Thick layered river deposits create a plain in front of the glacier. At a later point in time, the river cut through its own deposits, forming flat terraces stranded high on the valley slopes. 

Encounter on a lonely trail. After walking alone for hours, it is always fun to meet the locals travelling between villages. We met this small caravan between the settlements of Burfu and Bilju. Permanent link: Encounter at Bilju.

 A house in Milam village basks in the October sun. 

The Goriganga snakes its way down Milam Glacier through the fabled Johar Valley. This location is a few kilometers downstream of the glacier. 

Near Milam Glacier! The actual glacier is about 4-5 km upstream of this location, but this is a good photo spot along the trail.

What a trip! I think late September to early October is really the best time to visit this area. The countryside is lush and you get clear views of the Himalaya. The local residents have still not migrated to lower altitudes and you can get to enjoy their company in the many hamlets along the way. However, this year, rains continued well into the second week of October. I feel with climate change there will be a greater unpredictability to October weather in the future.

Finally, a big thank  you to Emmanuel Theophilus, Malika, Kamala Pandey, and Munna Singh Nitwal for being such gracious hosts and making my trip so memorable.

A post on geology tips for trekkers is coming soon... 

Readings: Chamoli Debris Flow Disaster, Uttarakhand

The Himalaya are geologically and ecologically fragile. Despite this, the Indian government has repeatedly ignored advice from its scientists and has gone ahead with major infrastructure projects, which have not been assessed rigorously for the inevitable impact they will have on the surrounding environment, people and livelihoods.

The February 7 2021 Chamoli debris flow that destroyed two dams and killed scores of people with hundreds still missing is the latest example of how the natural tendency of Himalayan slopes to fail combines with steel and concrete to cause enormous damage. 

Here is a short list of readings of this event and Himalaya infrastructure projects.

1) Dr. Dave Petley has put together a sequence of events based on crowd sourcing satellite imagery. This was a remarkable example of experts collaborating to pinpoint the location and cause of this debris flow within just a day. 

The catastrophic landslide and flood in Chamoli in Uttarakhand: the sequence of events.

 2) M. Rajshekar explores the messianic drive of the Central and the Uttarakhand government to build dams in the Himalaya. 

Modi said he would revive Ganga but his government is doing the opposite by reviving dams. 

3) R.Shreedhar, an experienced earth scientist working in the Himalaya writes a fine essay about the neglect of science and the political economy of Himalaya dam building.

The Science and the Political Economy of the Rishi Ganga Flood.

4) The title of this essay by Nivedita Khandekar says it all.. "We have learnt nothing from the 2013 Uttarakhand Disaster".

We have learnt nothing from 2013 Uttarakhand disaster.

 

Hutton On Erratics

 "There would then have been immense valleys of ice sliding down in all directions towards the lower country, and carrying large blocks of granite to a great distance, where they would be variously deposited, and many of them remain an object of admiration to after ages, conjecturing from whence, or how they came. Such are the great blocks of granite which now repose upon the hills of Saleve".

... James Hutton : Theory of the Earth (1795). 

This passage is quoted in Jamie Woodward's book The Ice Age: A Very Short Introduction, and it is one of the earliest attempts to explain 'erratic boulders'. These are boulders sitting on a surface made up of a different rock type than the boulder, indicating that the boulders have been transported from a far away terrain. The great blocks of granite observed by Hutton were scattered on a limestone landscape that was part of the Jura mountains on the border between France and Switzerland.  Just how these boulders got to their present location was the subject of a lively debate in the late 1700's and the 1800's. Hutton suggested they were brought there by glaciers. Other naturalists, taking inspiring from Scripture, proposed that they were transported by Noah's flood. 

Erratics implied that glaciers must have been much larger in the past. Hutton never developed his thinking about glaciers into a full explanation. That would take several more decades of debate. Erratics found in Alpine regions and on the European and North American temperate plains became part of a growing body of evidence for past climate change.

Closer to home, the picture below shows an 'erratic' made up of a high grade metamorphic rock and sourced from the mountains seen in the background. The location is Darma Valley, Kumaon Himalaya.

Field Photos: Glacial Deposits Of The Darma Valley, Kumaon Himalaya

During my recent trek to the Panchachuli Glacier in the Kumaon Himalaya, I obsessed about observing changes in metamorphic grade of the Greater Himalayan Sequence on the trek route and also about finding the South Tibetan Detachment fault system. I wrote about this in an earlier post.

But there were other interesting geological observations too. The Panchachuli Glacier has left a thick record of glacial deposits. The river Dhauliganga originates from this glacier. Along this river valley, glacial deposits can be observed to a distance of at least 5 kilometers downstream of the present location of the snout of the glacier, indicating that the glacier was much more extensive in the past. Tributary glaciers flowing out of the ranges east of the Dhauliganga have also left an extensive record in the form of thick fluvio-glacial deposits. These can be observed as far south as the village of Baaling.

We heard anecdotes in village Dugtu about how this glacier was much bigger in living memory and how it has been receding rapidly in the past few decades. On one level such stories are believable because studies of Himalayan glaciers have shown that many of them have been shrinking over the past few decades (ref). This is partly due to anthropogenic global warming, but glacial response to warming may be varied due to local variations in topography, precipitation and wind conditions. Some glaciers don't show retreat while some are actually seen to be expanding. Overall though, there a substantial ice loss observed across the Himalaya. Exactly how much of that is due to recent global warming and how much, as some scientists caution, due to natural factors is still being studied. Sustained warming though will cause these glacier to shrink further over the next century.

There is also a longer geological story of glacial advance and retreat written in these deposits.

I've embedded below an annotated interactive map of the glacial deposits of the Dhauliganga river valley in the Panchachuli Glacier area. This will enable readers to zoom in and recognize the various glacial landforms present in the valley. You can also access it via this Permanent Link.



The annotations depict:

a) The dark blue lines are the snout of the glacier.
b) The light blue lines are the recent terminal moriane fields.
c) The pink lines are older lateral moraines.
d) The yellow lines are outlines of older fluvio-glacial deposits
e) Numbers 1 -12 mark the locations of glacial deposits.

I have mapped only a few representative examples of each of the feature types. Readers can use these to explore similar features scattered throughout the valley. 

Location 1: This is the snout of the glacier. It is a mass of ice and frozen mud. The river Dhauliganga emerges out of an ice cave.

Location 2: Taken from near the snout of the glacier looking downstream. Ridges of the terminal moraine can be seen in the foreground. The arrows in the background outline a ridge of an older lateral moraine. Notice how the ridge decreases in elevation downstream suggesting that the terminus of this older glacial phase in somewhere nearby downstream.

Location 3: The older lateral moraine can be clearly seen as a sharp ridge line (arrow) separated from the valley wall by a depression. 

This moraine top is a few hundred meters above the valley floor implying that the glacier was thicker in the past. When was this lateral moraine deposited? It may be at least a few hundred years old. In the Garhwal Himalaya, similar older lateral moraines close to the glacier has been dated to be several hundred years old. They have been interpreted to be a result of glacial growth and deposition during the Little Ice Age, a period of earth cooling and climate instability that lasted from around the 1300's to the mid 1800's (for more on this climatic episode, I recommend Brian Fagan's book The Little Ice Age: How Climate Made History 1300-1850).

Location 4: A view of the glacier and an older lateral moraine (arrow) on the other side of the valley.

Location 5: Further downstream are thick glacial deposits. The river has incised or cut through these sediments. As a result the deposits form flattish plateaus or terraces that hug the mountain slopes. Village Dugtu, where we stayed, has been built on top of one such glacial terrace. The arrow in the top picture points to an exposure of these glacial deposits. A close up of this deposit is seen in the bottom picture. Notice the extremely ill sorted texture. Such ill sorted sediment deposited by glaciers is called Till. Large boulders are mixed in with  gravel, pebbles and much finer sized rock flour (the light to brown colored matrix).

Location 6: Another exposure of a glacial deposit near Dugtu. Again, notice the ill sorted deposit. However, at the top is a well sorted pebbly layer. This suggests deposition in more vigorous flowing water. Glacial retreat from time to time would have resulted in the establishment of a fluvial regime and deposition in these streams. These deposits may be a few hundred to several thousand years old.

Location 7: The glacial terrace on which village Dugtu is built is seen in the lower right corner. Farther away is village Philam built on the thick fluvio-glacial deposits of a tributary glacier originating in the range east of Dugtu. At village Dugtu, the east flowing river Dhauliganga makes a sharp southerly turn. The river has cut through these deposits and the slopes of the valley are thickly forested suggesting the great antiquity of these deposits.

Location 8: A nice view of glacial deposits south of village Baun along a smaller tributary of the  Dhauliganga. Notice the waterfall!

Location 9: A walk right through these thick fluvio-glacial deposits along a forested section of the valley slope. Again, notice the ill sorted nature of the deposits. Glacier are viscous and cannot sort sedimentary particles like water or air can. The result is a jumble of boulder, gravel and rock flour.

Location 10: Another cliff made up of fluvio-glacial deposits. I'm calling the deposits east of Dugtu as fluvio-glacial, since I observed intervals which show layering. This suggest deposition in water, either in streams or in melt water lakes and ponds that form in front of glaciers.

Location 11: A thick sequence of fluvio-glacial deposits along the Dhauliganga river. If you zoom and pan the satellite image you can recognize these terraces  southwards almost up to the village of Baaling.

I did not observe such deposits south of Baaling. However, there are smaller glaciers, such as the Naagling glacier, originating in the ranges on either side of the Dhauliganga. There would be smaller deposits scattered in these tributary valleys.

I have been vague about how old these deposits could be. If we assume that the Panchachuli glacier would have attained its maximum extent in the Pleistocene during the Last Glacial Maximum about 20,000 years ago, then the deposits furthest away from the present location of the glacier would be the oldest. As the glacier recedes one should find younger and younger deposits closer to the active glacier.

A study by Dirk Scherler and colleagues in the Garhwal Himalaya found such a pattern. They studied deposits of the prominent Jaundhar Glacier and the Bandarpunch Glacier in the Tons Valley. I've posted below a map showing the interpreted ages of deposition of glacial sediments.

 Source: Scherler et. al. 2010

Notice how the oldest deposits are further away from the present location of the glaciers (eastern most extremity of the map). These oldest deposits point to the maximum extent of the glacier that was reached in the Pleistocene during the Last Glacial Maximum.  However, the decreasing ages of the deposits upstream aren't the result of a uniform recession of the glacier. Instead, they point to several glacial episodes during which the glacier advanced, then receded, and then advanced again during the Holocene. Their data shows five such episodes of glacial growth dated to approximately 16 ka (ka = thousand years ago), 11-12 ka, 8-9 ka, 5 ka and less than 1 ka.


It turns out that the climate history of the Holocene is not one of uniform warming since the end of the last glacial period. The earth has gone through several minor cooling phases during the Holocene. The well known Younger Dryas Event around 12.9 -11.7 ka is one example.  Some studies suggest cooling episodes around 8.2 ka  and around 4.2 ka . And there is the Little Ice Age during the last millennium.

Another climate dynamic is fluctuating monsoon strength through the Holocene. The authors don't favor the explanation that these periods of glacial growth were triggered by global cooling events.  They argue that glacial growth corresponds to small phases of increased monsoon strength interrupting a longer trend of decreasing monsoon strength. More moisture means more snow and glacial growth. Since the long term trend in this part of the world is one of decreasing monsoon strength, every successive phase of glacial growth was smaller than the previous, resulting in younger and younger deposits upstream. The Little Ice Age deposits (which were likely driven by global cooling and not necessarily increased precipitation) mark the last major phase of glacial growth.

How are these deposits dated? Scherler and colleagues use a technique known as cosmogenic nuclide dating. This technique is one way to date the timing of surface exposure. Glaciers carry rock debris. These form a layer below the moving ice. When the glacier recedes the rock debris is deposited as a moraine or as an erratic boulder. It is exposed to the atmosphere and starts getting bombarded by cosmic rays. Energetic cosmic ray neutrons falling on atoms of minerals like quartz results in spallation reactions. This means that the collision of neutrons is energetic enough to fragment the nucleus. Oxygen bound up with silicon in the mineral quartz gets converted to an isotope of Beryllium (10Be). The amount of nuclides generated this way is proportional to the length of exposure. By measuring the amount of 10Be and comparing it with other isotopes, an 'exposure age' is estimated. This is essentially the age of glacial recession and the deposition of glacial sediment.

Samples have to been selected carefully for this method to give a true estimate of surface exposure and deposition. Care must be taken to avoid sampling rocks that have been repeatedly buried and exposed. Rocks which show signs of being subjected to prolonged glacial erosion are selected since  erosion will remove outer shells of material that may have accumulated nuclides during an earlier period of exposure.  Debris with a polished surface or with striations and grooves generally suggest subglacial transport and prolonged glacial erosion and are preferred samples.

 The figure below taken from the same study shows the reconstructed glacial extents using exposure dates of the moraine sequences in the upper Tons Valley.

Source: Scherler et. al. 2010

Such dating of glacial deposits at other locations in the Garhwal Himalaya (ref) tell a similar story of glacial growth and decay over the Holocene. And what about the Pleistocene? Is there evidence of older glacial cycles in the Himalaya? There are many studies that have identified glacial phases during the Pleistocene as well. For example, in northwest Garhwal, the Bhagirathi Glacial Stage has been dated to 63 ka (ref). And in the Ladakh Himalaya the oldest glacial stage has been dated to 430 ka (ref). Pleistocene ice ages have impacted glacial dynamics in the Himalaya too although more work needs to be done to understand the specific mechanisms of glaciation.

Location 12: Its back to the Dhauliganga valley floor. This moraine ridge (arrows) may be the remnant of an older terminal moraine. It is located about 2 kilometers downstream of the glacier.

The Panchachuli and other glaciers in the Kumaon region to the east of the Garhwal will also have their own history of past glory and recession. How much of the retreat of the Panchachuli and other Kumaon glaciers due to recent global warming?  And what is its fate? Hopefully, someone will study them with more precision in the future.

Field Photo: Glacial Erratic

Inspired by this xkcd comic:

I saw quite a few of these glacial erratics in the Dhauliganga river valley around the villages of Dugtu and Dantu. Here is my friend sitting on one of them.

This boulder is a high grade gneiss. It is an erratic because the surrounding bedrock is all low grade phyllite and slate. The source of the high grade gneiss boulder is the snow capped range you see in the background. These are the Panchachuli peaks and the Panchachuli glacier has eroded, transported and deposited gneiss rocks all the way down the valley onto a different bedrock.

The photo below shows another erratic from this valley. If you look closely it is a mixed rock made up of high grade gneiss intruded by light colored granite. A big patch of dark grey banded gneiss is visible in the lower right corner of the boulder. The cliffs in the background and the substrate on which the boulder rests is low grade phyllite.

And a long view of village Dugtu with glacial erratics strewn all over the hill slope (blue arrows).

I have been promising a post on the glacial deposits of the Dhauliganga river valley. That post will come soon. Meanwhile, here is a view of some of the moraines I saw near village Dugtu.  Photo taken from near the snout of the glacier facing downstream.

The linear ridge in the center of the photo made up of rust, brown and light colored boulders is a medial moraine. It was formed when two glacial streams carrying debris along their edges joined. As these glaciers receded the debris along their edges (lateral moraines) coalesced and formed a ridge in the center of the valley. You can see the milky white colored Dhauliganga river flowing to the right of the ridge. The blue arrows to the right of the picture high up along the mountain slopes point to older lateral moraines deposited when the Panchachuli glacier was thicker and extended further down in the valley...

more on these deposits later..

Are Himalayan Glaciers Retreating?

Open Access in Current Science- A remote sensing survey of 2018 glaciers across the Himalayan arc for the time period 2001 -2010 was carried out. Change in snout position was compared. The majority of glaciers over the last ten years show stable snout positions. About 12% show retreat and only 0.9% show advancement. Himalayan glaciers are retreating though. Studies that cover larger time periods have shown that studied glaciers have been in retreat over all of the last century with the largest retreats from the mid 1970's to the late 1990's. Glaciers have been naturally shrinking since the last Ice Age ended with few reversals such as the younger Dryas and the Little Ice Age, but the past 100 years or so are of interest to us due to the impact of anthropogenic global warming.

Glacial retreat may have slowed down in the last decade and no doubt given the complex response of ice masses to their situation in a particular topographic setting and temperature changes such variations in rates of change of glacier decay will continue as the earth warms. Besides, as other water experts have pointed out , the big problem with interpreting the true significance of Himalayan glacier behavior is the lack of crucial baseline data for a) the amount of snowfall in the various Himalayan glacial source areas and b) much of the reporting of changes in glaciers present area changes and not changes in volume. The volume of ice corresponds to the volume of water held, so any assessment of damage to north Indian river supply must study volume change of ice as glacial melt contributes substantially to Himalayan river water flow. Furthermore, such data if it does exist and that collected in the future must be made public to be examined by as many experts as needed and not kept secret as has been the case with Himalayan river water data in the past. So, a lot more work in terms of basic data gathering needs to be done. 

In any case such larger scale studies are useful pointers to regional trends and for pinpointing areas deserving more detailed studies.

Abstract:

The Himalayan mountain system to the north of the Indian land mass with arcuate strike of NW–SE for about 2400 km holds one of the largest concentration of glaciers outside the polar regions in its high-altitude regions. Perennial snow and ice-melt from these frozen reservoirs is used in catchments and alluvial plains of the three major Himalayan river systems, i.e. the Indus, Ganga and Brahmaputra for irrigation, hydropower generation, production of bio-resources and fulfilling the domestic water demand. Also, variations in the extent of these glaciers are understood to be a sensitive indicator of climatic variations of the earth system and might have implications on the availability of water resources in the river systems. Therefore, mapping and monitoring of these fresh  water resources is require d for the planning of water resources and understanding the impact of climatic variations. Thus a study has been carried out to find the change in the extent of Himalayan glaciers during the last decade using IRS LISS III images of 2000 /01/02 and 2010/11. Two thousand and eighteen glaciers representing climatically diverse terrains in the Him a-laya were mapped and monitored. It includes glaciers of Karakoram, Himachal, Zanskar, Uttarakhand, Nepal and Sikkim regions. Among these, 1752 glaciers (86.8%) were observed having stable fronts (no change in the snout position and area of ablation zone), 248 (12.3%) exhibited retreat and 18 (0.9%) of them exhibited advancement of snout. The net loss in 10,250.68 sq km area of the 2018 glaciers put together was found to be 20.94 sq km or 0.2% (2.5 % of 20.94 sq km).