Documenting history: Google Earth Images of the Teesta Valley before and after the Oct 2023 GLOF disaster.

Google Earth has recently updated its satellite imagery of the Teesta Valley, and high-resolution images from as recently as 2026 are now available. This allows us, for the first time, to view satellite imagery of the entire Teesta Valley following the devastation caused by the GLOF of 3–4Oct2023 from South Lhonak lake in North Sikkim.

It is unfortunate that satellite images from 2023 or 2024 are not available, as these would have revealed the true extent of the destruction in the immediate aftermath of the GLOF. The 2025/26 imagery, by contrast, shows many locations after significant repairs and reconstruction have already taken place. Also a word of caution here: the updated image and the older image are taken at different times and months of the year as such show shadow areas and colors differently.

Nevertheless, these images provide an important historical record of the largest GLOF in the Himalayas. When juxtaposed with earlier images of the same areas from 2022, they reveal the extraordinary scale and humongous power of nature as the GLOF swept down the Teesta Valley.

STH surveyed the GLOF-stricken areas soon after the disaster, and we already have a substantial report on the event in this blog. In this photo report, I have supported the satellite images with photos of the event from the ground in order to provide a closer look at the devastation.
For those interested, I have also uploaded  a presentation on YouTube, with approximate timelines and details of the disaster. Scientific details on the GLOF are available here.

1. Areas near South Lhonak lake (26°51.419’N 88°26.602’E)

Google Earth images of 2018 (top) and 2026 (below)

Slope profile from A (4472m) to B (3292m) along the river valley -distance 14.7km

2. Lachen town area (27.7167° N, 88.5578° E)

 

Google Earth Images of 2022 (top) and 2025 (below)

Slope profile from A (3278m) to B (2235m) along the river valley -distance 14.4km

3. Areas north of and near to Chungthang (27.613133° N 88.631783°E)
 

Google Earth Images of 2022 (top) and 2025 (below)

                            The Teesta Valley north of Chungthang, December 2023. 

The October 2023 GLOF transformed the valley into a vast corridor of destruction, scouring away entire forests and carrying millions of tonnes of rock, sediment and debris downstream. Buildings, roads and hydroelectric power infrastructure were damaged or swept away, leaving a devastated landscape in its aftermath.

The army lost a lot of hardware, munitions and equipment in the GLOF and the ammunition depot at Munshithang just north of Chungthang was all but wiped out.

4. Chungthang town (27.6045° N  88.6456° E)

                                                    Google Earth Images of 2022 (top) and 2025(below)

Chungthang, the gateway to North Sikkim, sat at the scenic confluence of the Lachen and Lachung Chu (Chu means river in Tibetan). This strategic town was tragically altered around midnight on 04Oct2023, when the GLOF surged down the Lachen Chu. The deluge obliterated much of the town.

Chungthang town on 05Oct2023.

Drone image of Chungthang town, on 17Nov2023 when we visited the place.

5. 1200MW Teesta III dam at Chungthang (27.6045° N  88.6456° E)

Google Earth Images of 2022 (top) and 2025 (below)

Chungthang town owed much of its development to the presence of the 1200MW Teesta III dam (or the Sikkim Urja dam) which was commissioned in Feb 2017 and the town became a tourist hub for travelers going towards Lachen or Lachung in North Sikkim.

The GLOF of Oct2023 destroyed the dam, shortly after midnight on 04Oct2023. The precise time of collapsed may never be known as it was pitch dark, raining with the noise of the GLOF hitting the town. In this melee, residents of the town were busy scrambling to higher ground to save their lives to notice when the dam collapsed. They only came to know about it at dawn on 04Oct2023.

  Image of the collapsed Teesta III (Sikkim Urja) dam taken a few days after the dam was         destroyed.

Drone STH image of destroyed dam with Chungthang town in background -17Nov2023

6. Hanuman Mandir (south of Chungthang - 27.58310°N  88.65591°E)

Google Earth Images of 2022 (top) and 2025 (below)

 7. Naga Village (Mangan district, North Sikkim  27.545367°N 88.628383°E)

Google Earth Images of 2022 (top) and 2025 (below)

The village of Naga (Mangan district, Sikkim), located along the Mangan-Toong road suffered catastrophic landslides after the GLOF swept past it in the valley below. Many residents have since left the village for safer places.

                   Drone image of Naga village landslides taken by STH on 17Nov2023

8. Rangpo town (27.175° N, 88.530° E)

Google Earth Images of 2022 (top) and 2025(below)

The GLOF struck Rangpo—a bustling commercial and transit hub in the Pakyong district—in the early hours of 04Oct2023. Thanks to early warnings received on cell phones from friends and relatives upstream, most residents managed to scramble to higher ground. However, those who did not heed the alerts were tragically swept away.
The Teesta River rapidly submerged the low lying areas of IBM complex and bazaar in the northern part of the town. When the floodwaters finally receded, they left the entire bazaar buried under more than 10 feet of sludge and sand.

        Telephoto image of Rangpo on 06Oct2023 when STH visited the town.

Heavy construction equipment buried under more than 10 feet of sludge and sand at IBM bazar in Rangpo - photo by STH on 06Oct2023

Portions of buildings being excavated in IBM bazar, Rangpo in Dec2023 after the GLOF buried everything under more than 10feet of sludge on 04Oct2023.

Drone image of IBM bazar on 19Mar2025. Much of the sand and debris has been cleared and the Red and Green buildings seen in earlier image are now clear of the sludge.


9. Melli town (27.0906°N 88.4561°E)

  Google Earth images of 2022 (top) and 2025 (below)

Melli is a small town, on the banks of the Teesta river, which straddles both the states of Sikkim and West Bengal (Kalimpong district). The GLOF of 04Oct2023 affected both states.
The top Google Earth image of 2022 shows the sports stadium and parts of Melli town prior to the GLOF.
The lower image shows the impact of the GLOF where the Teesta river now flows on the edge of the stadium. The river flooded the stadium during the GLOF and since the river level has risen by almost 10-15 feet after the GLOF, it routinely floods the stadium after heavy rain (see below)

Drone image Melli stadium of Sep2024 covered with sludge and sand

 

10. Tribeni 
(Confluence of Rangeet and Teesta river - Kalimpong district - 27.079767°N  88.430950°E)

Google Earth images of 2021 (top) and 2025 (below)

Tribeni Covid Hospital is located at the confluence of the Rangeet (dark blue) and Teesta rivers and was used effectively as a isolated treatment centre for Covid patients. The GLOF reached here in the early morning of 04Oct2023 and submerged the road access to the area  from Teesta bazar as well as severely damaged the structure and the compound of the hospital.

Tribeni Covid Hospital on 24Jul2024, approximately one year after the GLOF hit the area.

11. Teesta Bazar (27.059722° N 88.426111° E)

Google Earth images of 2021 (top) and 2025 (below)

The GLOF crashed into Teesta bazar at around 4.00am on 04Oct2023. Residents we interviewed talk about a wall of water coming towards them with cars bobbing up and down in it with headlights on - like little toys in a bathtub. Praveen Chhetri my young colleague from STH reached Teesta bazar the same morning and has photographed some of the most dramatic photos of a GLOF in progress.

The GLOF hitting the Teesta bazar on 04Oct2023 and the same area and buildings seen below in a photograph of 21Jul2024.

Coincidentally all the above photos are approximately of the same area in Teesta bazar as the photo from the 04Oct1968 Darjeeling-Sikkim disaster. See photo below:

 

 

12. Geil Khola (27.029213° N  88.427925°E) 

Google Earth images of 2022 (top) and 2024 (below)

The GLOF reached Geil khola , a transit point on NH10 near the Teesta Bazar, in the early hours of 04Oct2023 and quickly swallowed up the low lying areas of the hamlet. The half buried houses in the red circle are visible in the lower satellite image.
A more recent image of the same area showing the devastation by the GLOF is placed below:

I have documented these Google Earth images of the Oct2023 GLOF disaster along with supporting photos by STH and other known persons in an attempt to preserve a photographic record of a momentous disaster in our region.
While so doing, I found that most of the updated Google Earth images were from 2025, two years after the GLOF took place, nevertheless they do provide an visual indication of the scale of the disaster when compared to earlier images of the same region.
For those who are would like to know why the imagery is clustered around two areas (see map), I would say, these were the areas where the most devastation took place and also where population density is the highest.

My thanks to all those whose photos I have used in the above report

Praful Rao

savethehills@gmail.com

9475033744

SaveTheHills photo exhibit on 'The Teesta Valley GLOF disaster - the unheard voices' renewed till April2028 (by Social Documentary Network).

Exactly a year ago, I published a report on the Social Documentary Network (SDN) titled “Teesta Valley GLOF Disaster – The Unheard Voices.”

For those unfamiliar, SDN is a ‘global platform for documentary photographers and visual storytellers, with a strong focus on social, environmental, and human-rights issues, featuring the work of around 3,000 photographers worldwide’ (ChatGPT).

A few days ago, I was notified by SDN that the GLOF exhibit was due for renewal, which involved a fee in US dollars. However, there was also an option to apply for a fee waiver. I’m happy to share that considering our work, SDN has graciously waived the renewal fee until Apr2028.

This means our Teesta Valley GLOF exhibit will continue to remain accessible on a respected international photojournalism platform. I have also updated and refined the exhibit, and it is now available to view here.

I would urge you to take a look and share it further. The disaster remains largely unknown beyond the region, and greater awareness is essential so that the scale of the tragedy—and its continuing impact—is not forgotten.

Praful Rao,
savethehills@gmail.com
9475033744

Photo report on Teesta bazar and its vicinity - 21July2024

The Teesta valley GLOF, hit the town of Teesta at approx 4am on 04Oct2023 and caused much devastation which we have recorded in this blog here. What was clearly apparent then was that unless some urgent engineering steps and other short term measures to mitigate the impact of the GLOF were taken quickly, the whole area would again relive the disaster when the summer monsoons arrived.
Unfortunately, except for some very temporary measures like evacuating people to relief camps, doling out some compensation and reopening roads, we did not take advantage of the dry season when the Teesta river was more manageable and of course, we had the general elections of  April2024 which provided a good reason to sideline disaster management requirements of the GLOF.
I have visited the Teesta bazar area numerous times (I live in Kalimpong which is 17km from Teesta bazar and it takes me 40mins to reach there), interviewed affected people, given many presentations and written to the NDMA, SDMA's of Sikkim, W Bengal and other political representatives with a view to highlight the seriousness of the condition in the Teesta valley and especially in the low lying areas where the river is now flowing at elevated levels.
I spent 5hrs at the Teesta bazar and its vicinity again on 21July2024 and my observations are as follows:

Weather conditions in our area
   * The monsoon rainfall generally peaks in July but we still have not had really heavy and prolonged rain in our region.
   * IMD had issued 10 days of RED warning for heavy rain around mid June2024 and north Sikkim did get heavy rain on 13Jun2024. Impacts:
         - the Teesta river flooded parts of Melli, Teesta bazars.
         - Darjeeling-Kalimpong road was submerged,
         - NH10 is closed, mainly due to landslides at Likhu Bhir
   * However, for the past 6 days or so, we have seen a drastic decline in rainfall in our area due to the formation of a low pressure area in the Bay of Bengal. This has resulted in the water levels falling in the river as such the Darjeeling- Kalimpong road is open. However, NH10 continues to be closed for repairs since 01July2024.

Impact on Teesta River

View of the river from the Teesta bridge and looking northwards towards Sikkim. Even though water levels had reduced because of less rain, the river was still very swift and flowing bank to bank

View of the river from the Teesta bridge looking southwards towards Siliguri. The Darjeeling-Kalimpong road on the right is now useable - but only so long as the water level remains low.

Teesta flowing from bank to bank near Likhu bhir (27 02 27.3 N  88 25 39.6 E, Elev 240m)

Teesta river opposite Geil Khola. This is the only place (27 01 48.3 N 88 25 43.0 E, Elevn 225m) where I saw that the river has moved away from a populated area and is now confined to the opposite bank - everywhere else, it was flowing from bank to bank.

Teesta river at Rabi Jhora (27 03 0.5 N 88 25 38.6 E, Elevn 534m) where it is flowing at the same level as NH10. Teesta bridge linking Sikkim and Kalimpong can be seen in the background.

Impact on Populated Areas
I visited the Teesta bazar and tried to access Melli (S Sikkim) and Bangay Bazar in the same area but could not do so due to a landslide and a flooded bridge. It is a grim and sorry tale which I witnessed in the entire region - since the highway is closed, road traffic has drastically reduced in all the areas as such business is dead for those who have restaurants and tourism related work in the valley. Rafting, another money earner for the local youth has also stopped due to the river being in spate.
The river is now running close to low lying populated areas and in the case of many homes and buildings, the Teesta river is lapping around in the ground floor rooms of the dwellers and I was told by a hotel owner at Melli (W Bengal side) that he has to keep checking the water level in the basement with a torch thru much of the night.
All this, with almost 3 months of rains ahead.

Melli (South Sikkim) - 27 05 12.5 N 88 27 9.7 E, Elevn 230m
Melli is a small town in South Sikkim located across a bridge over the Teesta river. I found that there was no vehicular access to Melli after the main road to the town was destroyed by a landslide MORE than a month ago.

All vehicles destined for Melli town were parked at a petrol station almost a kilometer from the town from where people had to walk to/from the town. We were told that the carriage charges by porters for ferrying goods to the town was Rs 100 per 10Kgs!

This landslide took place more than a month ago and has cut off vehicular access to Melli town in Sikkim since then. When I asked why the repair was taking so long, I was informed by the locals that whatever the bulldozers cleared during the day is nullified at night with parts of the hills crumbling and blocking the road again. One has to walk to/from Melli town on an 'upper route' above the landslide area (27 05 13.4 N 88 27 9.7 E, Elevn 226m).
Time constraints prevented us from walking to the town but we know that the Melli stadium which was painfully cleared of debris all thru winter was once again flooded on 13Jun2024.

Geil Khola (27 01 41.2 N 88 25 40.0 E, Elevn 230m)
This is a sleepy little hamlet on NH10 which was badly impacted by the GLOF last year. The village was not affected by the deluge of Jun2024 and nothing seems to have changed since Oct2023. All the houses which were buried then, are still buried and with the highway closed for 3 weeks, most of the small restaurants and hotels were also closed.

Geil khola on 21July2024

Bangay Bazar (26 59 58.3 N 88 26 35.8 E, Elevn 211m)
We have covered this area in an earlier blog here when 19 homes had been inundated during the GLOF. The conditions seemed similar when I visited the place on 21July2024 - Relli river was again flowing over the bridge to the village and there seemed to be little activity in the village itself.

Teesta Bazar (27 03 23.1 N 88 25 30.4 E, Elevn 220m)
Teesta bazar was badly affected by recent rains in June and July2024 and we have reported on the condition of Bhasuwa or Krishnagram in the town, in our last blog. Our observations on places we visited is as follows:

Many homes and structures which are NOW on the banks of the river are submerged. Locals clearly state the river 'was always way down below' and that it is only post GLOF2023 that the river is so high and so close.

Submerged homes on the banks of the Teesta and the Darjeeling-Kalimpong road at Teesta bazar which also routinely gets flooded during heavy rain in the valley.

The Teesta river runs close to all these houses which today find themselves on the banks of the river at Teesta bazar. Politicians and media people visiting these areas often ask the people 'why did you all build your homes so close to the river?' To which they answer, 'No sir! we did not build our houses close to the river, it is the river which has come close to our homes' - this is wholly correct.
People still live in most of these houses and the river levels seen here are after 6 days of little or no rain in our region.

GTA Covid Hospital at Tribeni

We could not visit the hospital since there is no road access.

Condition of NH10 and roads

National Highway 10 (NH10) - closed since 01Jul2024

In the time available to us on 21July2024, we could only cursorily survey approx 12.5 km of the NH10 which lies between Melli and Teesta Low Dam Project III. This section of NH10 is also the most problematic maintenance-wise and has always had some major landslides which have continuously troubled both the agencies who maintain the highway and also travellers. However, after the 2023 GLOF, the scenario has changed entirely with the Teesta river flowing almost at road level in many places - causing the saturated road bench to slump into the river at places. I have placed photos of areas which are damaged below:

This is close to the Teesta bridge and failure of this slope would impact both NH10 and the Darjeeling-Kalimpong road which is directly below (27 03 8.0 N 88 25 36.9 E, Elevn 588m).

This is the infamous 27th Mile landslide which troubled us for years. After suitable treatment, it had somewhat stabilized recently and it remained stable even after the GLOF. The recent rains seems to have reactivated it. There was a bulldozer stationed here, indicating it has become a threat (27 01 1.6 N 88 26 5.6 E, Elevn 236m).

Image of Likhu Bhir landslide in Apr2024 when the highway was closed for repair (credit: Mukesh Sharma, Kalimpong)

Likhu Bhir (both photos), is an old landslide which was stable for years, until the GLOF activated it on 04Oct2023. It is a very troublesome slide on NH10 now (27 02 34.8 N 88 25 43.3 E, Elevn 250m)

With a fast flowing river so close to the road bench, parts of the road slumping into the river is common. This is at Likhu Bhir and the workers informed us that IRCON tippers were dumping excavated soil from tunnels into the river to 'push' it away from the road.( 27 02 11.6 N 88 25 38.4 E, Elevn 234m)

This road slump is near Baluatar, seen in the distant (27 00 41.2 N 88 26 23.7 E, Elevn 262m)

Rabi Jhora, which is just a stones throw from Teesta bazar. Notice that the level of the river is almost the same level as the highway ( 27° 2'59.71"N, 88°25'35.06"E Elevn 534m).

NH10 approximately opposite Melli. The edges of the highway are slumping into the river at many places (27 04 56.4 N 88 26 47.2 E, Elevn 285m)

Laborers houses on the river bank on NH10 near Melli. Some have abandoned their homes but it appeared that some were steadfastly staying put (27 05 1.2 N 88 27 4.7 E,
Elevn 233m).

NH10 opposite Melli town. With the river flowing at much higher levels due to the GLOF, parts of the saturated highway are crumbling into the river. This phenomenon was observed even before the GLOF and largely due to dam activity but now with the GLOF, this is more frequent.

Darjeeling - Kalimpong (road via Teesta Bazar)
A large section of the above road was submerged by the GLOF 04Oct2023 and was only reopened for use by light vehicles on 21Oct2023. It was plain to see that with the river flowing barely a few feet below the road level around the Teesta bridge, that the road would again be inundated when the river level went up.

Darjeeling- Kalimpong road after the GLOF on 22Oct2023 . Notice the level of the road and the river.

That is exactly what happened on 13Jun2024, when the river levels rose following heavy rains in  North Sikkim.

Photo of flooded Darjeeling- Kalimpong road in mid-Jun2024 (courtesy - Mukesh Sharma, Kalimpong)

When we visited Teesta Bazar on 21July2024, after 6 days of almost dry weather, the river had receded and the road was dry except for small patches of water. Yet what we were told by the locals near the road is that the moment it rains heavily, the road would again be submerged.

The Darjeeling-Kalimpong road on 21July2024. This entire road was flooded on 13Jun2024 and will again be flooded the moment the Teesta river level rises due to heavy rain in the catchment areas. So traveling to Darjeeling and back (normally a 3 hour trip) becomes a guessing game. Add to the fact that hundreds of tourists normally plan their holidays between Darjeeling and Gangtok and have to transit thru this area - while going to Darjeeling - for them it will be a harrowing and uncertain experience.


Tribeni hospital access road (27 04 2.4 N L 88 25 36.5 E, Elevn 223m) :
Road access to the hospital at Tribeni was never restored after the 4Oct2023 GLOF because the Teesta river kept parts of the road always submerged. This was so when we photographed the road on 21July2024 (see top photo)

Entry point of the Tribeni Hospital access road on 21July2024. I have visited this area very often over the past year and with each visit noticed the river eroding more parts of the access road. An image of the same area in Nov2023 but viewed from the opposite direction is below.

Much of this area is now under water and whereas vehicular movement was possible in Nov2023, it is impossible now.

Recommendations

1. We, once again request that an independent team of experts and scientists visit the Teesta Valley DURING the monsoons 2024 to see and understand the devastation and plight of affected people in Sikkim and W Bengal.

2. Appropriate engineering mitigation measures to control the river and protect population centers and roads, along with proper allocation of funds and resources in the entire Teesta valley maybe implemented based on the report of such an expert committee.

3. Mitigation measures in the affected areas maybe executed sooner than later, keeping in mind that no effective intervention can be undertaken during the monsoons when the river is in spate and our road communication is decimated by landslides.

Failure to take timely corrective action will mean repetition of this whole scenario once again in 2025.

Praful Rao
SaveTheHills
savethehills@gmail.com
9475033744