An event of Note : The 7th World Landslide Forum, to be hosted by India in November 2026.

Photo of a landslide from the first post in this blog of Sep2007 when SaveTheHills was formed.

SaveTheHills was formed in September 2007 in the aftermath of intense rainfall that struck North Bengal and Sikkim in the first week of that month. The resulting deluge triggered widespread landslides and devastation. We began documenting these events through the STH blog to build a lasting historical record of a recurring hazard that continues to trouble the region year after year.

Nearly two decades on, landslides remain at the core of our work and concern. It is therefore heartening news that the 7th World Landslide Forum (WLF7) will be hosted in Faridabad, India, under the auspices of Amrita Vishwa Vidyapeetham from 23–27Nov2026.

In this connection, while attending the first virtual TOWNHALL for WLF7 on 19Apr2026 (see below), we hope to participate in and learn from the forum in Nov2026.

Praful Rao
SaveTheHills
savethehills@gmail.com
9475033744

A post GLOF look at parts of Teesta Valley (Part - 2)

More than a year has passed since the devastating GLOF disaster of October 4, 2023, that swept through the Teesta Valley. We have extensively documented the catastrophe and its aftermath in this blog. Following the GLOF, the 2024 monsoon season brought further destruction, exacerbating the damage to already weakened structures, roads, and the environment.

In the photos below, we aim to capture the changes that have unfolded during this time. With another monsoon fast approaching, our repeated calls for mitigation efforts during this dry, non-monsoon period have largely gone unheeded except for the transfer of maintenance of sections of NH10 in West Bengal from the state PWD to NHIDCL, a step forward, which is widely regarded as too little, too late.

Sikkim

Sangakalang

Both these bridges on the river bed and a larger bridge which spanned the river were swept away during the monsoons of 2024.

Dzongu

Fidang

Dikchu town

NHPC Stage V dam (Dikchu)

Sikkim and West Bengal

Tar khola NHPC Power house

All drone images by Praveen Chhetri, Junkeri Studios, 9733185815

Praful Rao,
SaveTheHills
savethehills@gmail.com
9475033744

Community-Led Call to Action: 290 Signatures urging Immediate Disaster Mitigation in the Teesta Valley submitted by Darjeeling Himalaya Initiative and SaveTheHills

 

The following memorandum signed by 290 persons from Kalimpong, Darjeeling, and Sikkim has been submitted by Darjeeling Himalaya Initative and SaveTheHills to the Chairs of the NDMA, SDMA W Bengal and SDMA Sikkim:
_______________________________________

The Teesta Valley GLOF Disaster of October 2023: Impacts and Urgent Mitigation Needs Ahead of the 2025 Monsoons.

The Glacial Lake Outburst Flood (GLOF) and the subsequent hydro-power dam breach in the Teesta Valley in October 2023 brought widespread devastation, leading to tragic loss of life, severe damage to livelihoods  and assets as well unaccounted ecological devastation across Sikkim and West Bengal.

The disaster caused significant destruction to the National Hydroelectric Power Corporation’s (NHPC) infrastructure, agricultural land, forests, riverine ecosystems, transportation routes, and even critical military installations (Much of the devastation caused by the GLOF is documented in SaveTheHills’ blog http://savethehills.blogspot.com) Yet, despite the scale of the disaster, the response from state and central authorities have been inadequate, especially long term rehabilitation and restoration interventions at the relief, infrastructure and ecological level.
To further elucidate, we cite the case of fifty six families in the Teesta Valley (Kalimpong district)  who were displaced by the floods in Oct2023 and still continue to reside in relief centres. For these people who depended on the river for their survival, displacement has worsened their economic stability, and every day existence becomes a struggle for survival. Prolonged uncertainty worsens their mental distress, highlighting the urgent need for targeted interventions to restore their houses and livelihoods.
NH10, the lifeline of Kalimpong and Sikkim remained perilously unstable for much of the monsoons season and diversion of traffic from Sikkim via alternate routes added avoidable burden on transport services, infrastructure as well as the communities along the route.These vulnerabilities were exposed again almost throughout 2024 monsoon season and has severely reduced the tourist traffic to the region impacting  the economy of the Sikkim and Darjeeling Himalaya.

With only six months remaining before the 2025 monsoon, there is an urgent need to implement both structural and non-structural mitigation measures throughout the Teesta Valley. Effective action now can significantly reduce the impact of future floods, as such the implementation of these measures both in Sikkim and West Bengal in the valley is a vital necessity.
Central assistance will be imperative simply because the scale and complexity of the problem cannot be tackled at the state level.
The important issues at hand are listed below:

The Case for a Joint Sikkim-West Bengal Committee on Teesta Valley Flood Management

The October 2023 GLOF was one of the most severe glacial floods in the history of the Himalaya, affecting both Sikkim and West Bengal and needs to be responded to at a landscape level that is inclusive of both states. Each monsoon season, the Teesta River poses serious threats to both states, making collaborative management of the river and its surrounding regions essential.
A joint committee from both the states could address common issues and implement coordinated disaster management strategies that benefit both states.

Formation of an Expert Task Force

A dedicated task force of experts, drawn from geo-hydrology, environmental science, engineering, and sociology, should be formed to tackle the many challenges brought about by the GLOF. This task force must develop a comprehensive action plan that includes technical, financial, and social solutions for restoring and fortifying the region.

Structural Mitigation Measures

Construction of Embankments, Protection Walls, and Barriers

Embankments and barriers are urgently needed in low-lying, high-risk areas to prevent river overflow into settlements. Populated areas in the valley which are particularly vulnerable to flooding such as  those below the Teesta bridge along the Darjeeling-Kalimpong road, must be identified and remedial engineering solutions applied.

Channeling the River Flow

The natural flow of the Teesta River was disrupted by debris buildup from the GLOF, leading to riverbank overflow. The river must be re-channelized to prevent further damage to urban areas and infrastructure. Experts in fluvial geo-morphology and hydrological engineering can assist in deepening, widening, and redirecting the river to safer channels. NHPC’s technical expertise can be instrumental in this effort.

Road Engineering and Restoration

NH10, the key highway linking Siliguri and Gangtok, suffered extensive damage during the GLOF, resulting in economic losses and supply chain disruptions. Immediate restoration of this critical artery must be prioritized, along with repairs to alternative routes that have also deteriorated due to increased traffic and monsoonal impacts.

Bridge Repair and Reconstruction

The destruction of bridges in Sikkim and West Bengal has cut off many communities, hindering both economic activity and disaster relief efforts. Repair and reinforcement of these vital structures must be completed before the next monsoon season.

Reinforcement of Evacuation Centers and Relief Camps

Many evacuation centers and relief camps need urgent repairs and enhancements, such as backup solar power, to ensure they remain operational in the event of future emergencies.

Non-Structural Mitigation Measures

Early Warning Systems (EWS) and Communication Networks

Installing automated flood early warning systems (FLEWS) that deliver real-time alerts through sirens and mobile networks is crucial. Backup communication methods, such as ham radios and walkie-talkies operated by trained personnel, should also be implemented to ensure effective communication during emergencies.

Land-Use Planning and Zoning

Certain low-lying areas will remain high-risk zones even with structural protections in place. These areas should be designated for potential evacuation and resettlement of at-risk communities. Adequate compensation as decided by the expert group should be provided to affected victims and necessary support given to those relocating.

Public Awareness and Community-Based Disaster Risk Management (CBDRM)

Community preparedness is essential to build capacities and resilience during disasters. Awareness campaigns should educate residents on flood preparedness, evacuation procedures, and available insurance schemes. Additionally, evacuation drills must be regularly conducted to ensure communities can respond swiftly during emergencies.

Post-Disaster Financial Recovery Support

To aid in economic recovery, education on flood insurance and financial aid should be provided to residents and businesses, ensuring they have the tools to rebuild after a disaster.

Aggressive Afforestation Program

The GLOF caused widespread destruction of forests along the Teesta Valley. An aggressive reforestation initiative is needed to restore the valley’s ecosystem, prevent soil erosion, and help regulate the river's flow.

Conclusion

By implementing these crucial structural and non-structural mitigation measures, the Teesta Valley can be better prepared to withstand future monsoonal floods, protecting both lives and livelihoods. Urgent and coordinated action in the coming months is essential to prevent another disaster on the scale of the 2023 GLOF. The time to act is now, before the monsoons of 2025 arrive.

________________________________

We will submit the Memo to other officials as well.

Our thanks to all those who volunteered in making this community initiative possible

Praful Rao
Darjeeling Himalaya Initiative & SaveTheHills
9475033744

Roshan Rai
Darjeeling Himalaya Initiative
9932024812

Rainfall data of July 2024 of some towns in Sub-Himalayan W Bengal and Sikkim

IMPACT OF THE JULY 2024 RAINS AT TEESTA BAZAR:
Some young men at Teesta bazar had started a two wheeler repair business in this shop on the Darjeeling-Kalimpong road after they shovelled out all the sand and debris brought in by the 04Oct2023 disaster (notice the damaged ceiling fans). The rains of July2024 put an end to their business venture and dreams when the Teesta river, flowing in the vicinity and almost at the same level flooded their shop again during heavy rains.

Rainfall normally peaks in July during the monsoons after which the rainfall gradually declines in August and Sept with the monsoons normally exiting our region in October.
As is clearly visible from the top data, rainfall was heavier in the Dooars area and foothills of Kalimpong district (and Bhutan hills).
IMPACT
The amount and intensity of rainfall impacted road communication a lot with NH10 and the Darjeeling - Kalimpong road being closed OFF and ON thru the month.

Even Rohini road to Darjeeling from Siliguri was closed for some time on 02Jul2024

                                Landslide near Loreto School, Darjeeling - 05July2024

INFACT NH10, WHICH HAD CLOSED ON 01JULY2024, COULD NOT BE RE-OPENED FOR TRAFFIC UNTIL 31JULY2024 - WHICH WAS THE LONGEST DURATION THAT THE HIGHWAY WAS CLOSED CONTINUOUSLY EVER - ALL DUE TO THE TEESTA VALLEY GLOF OF 04OCT2023.

Landslide on NH10, at Andheri, near Rangpo on 16July2024.

A low pressure area in the Bay of Bengal which brought in a drier spell of weather in our region after the heavy rains in the first half of July2024.

My thanks to all our What's App group ('Hazard Alerts') members whose images and stories I have used in this post

Praful Rao
with
Yukta Acharya

SaveTheHills
Kalimpong district
Darjeeling-Sikkim Himalaya
savethehills@gmail.com
9475033744

Rainfall data of June 2024 of some towns in the Sub Himalayan W Bengal (SHWB) and Sikkim.

Even though the SW monsoons set in our region on 31May2024, the Darjeeling-Sikkim Himalaya started receiving significant rainfall only after the 10Jun2024.

IMD had issued appropriate warnings and press releases which attributed the heavy rain to 'a cyclonic circulation lying over northeast Assam & neighbourhood in lower tropospheric levels. and a trough which runs from East Uttar Pradesh to Nagaland'.

This weather system persisted for an inordinately long period resulting in a RED WARNING for heavy rain in our region which lasted for almost 10 consecutive days in mid Jun2024 and which caused a delay in the progress of the monsoons.
A senior meteorologist, I talked with said he had never witnessed this sort of phenomenon in his entire professional career:

Satellite image post in 'Hazard Alerts', our What'sApp group.

A typical rainfall pattern of thundershowers which are more often the norm in our region these days is shown below - these are sharp, heavy bursts of rain from Cumulonimbus (CB) clouds.

IMPACT

 

What is clear from the rainfall in June2024 is

• The heaviest rainfall took place in the plains of the Dooars with Alipur Duar clocking the highest rainfall.
  
• The foothills (Jhallong) also receive very heavy rain, some 4000mm annually and both our alternate roads (NH717A and the Gorubathan-Lava roads) to NH10 largely pass thru these foothills.
• Sikkim received more rain than Darjeeling and Kalimpong districts
• Even with this rain, many of our roads, especially NH10 are in tatters and unfortunately, things are not going to improve at least for the next 2 months or more - obviously, the Oct 2023 GLOF is the single most important factor causing this chaos.
  

While in the airforce many years ago, I was posted to Air Force Station Hashimara (which is very close to Alipur Duar) where receiving 200mm of rainfall overnight during the monsoons was not abnormal and the best part was NOTHING USED TO HAPPEN when we had such heavy rain. The river Torsa which flows close by never flooded and the drainage in the area used to swiftly take away the excess storm water into canals.
But we saw what happened in Mangan (North Sikkim), when they received 220mm rain on 12Jun2024 - there were many landslides, 6 people died and 1500 tourists were stranded in North Sikkim.
Bottom line: Our mountains are just too fragile and sensitive compared to the plains and we have to take care of them.

Praful Rao
with
Yukta Acharya

Kalimpong district
Darjeeling-Sikkim Himalaya
savethehills@gmail.com
9475033744

Views of the Teesta river after Cyclone Aila (May2009) and after the GLOF (Oct2023)

During our talks with GLOF affected people in the Teesta valley, they say that many officials, politicians and others often ask them why they built their homes so close to the river; to which they answer, 'No, we never built our homes close to the river - it is the river which has now come close to us!'

When I relate this during my talks on the Teesta valley GLOF, it often draws laughter from the audience - not realizing that I wholly share the views of the affected people:

The Teesta river which was once quite far from settlements has now moved closer to homes, roads and urban areas.

I visited the Teesta river on 11Jun2009, soon after Cyclone AILA (25-27May2009) and took photos of the river from the Teesta bridge. There were no dams those days but the river was still quite big because of the SW monsoons and Cyclone AILA.

After the Oct2023 Teesta Valley GLOF, again we made numerous trips to the Teesta river and photographed the river from almost the same spot on the bridge 14years later. I have placed both below for you to see how the river has moved closer to people's homes

Facing south (towards Siliguri)

Teesta, shortly after Cyclone AILA in Jun2009. Notice the level of the river visavis the Kalimpong to Darjeeling road on the right. The river was free flowing those days since the major dams on the Teesta were yet to be built.

Teesta river after the Oct2023 GLOF. Rainfall in our area totally stopped after 04Oct2023 (when the GLOF occurred) but the silt deposits had increased the river level as such it was flowing almost at the same level as the Kalimpong to Darjeeling road (on the right)

Facing north (towards Gangtok)

Cyclone AILA (27May2009) heralded in the SW monsoons that year as such the river is still quite large. Nevertheless the Teesta Bazar (left side) was not touched by the river even during Cyclone AILA

Our entire region had drought like conditions since the GLOF in Oct2023, yet the river stretches from one bank to the other and is flowing very close to homes in the Teesta bazar (left). The river is brown and loaded with silt and debris which is being dumped into the river by people excavating their homes and belongings all along the valley and also by the tunneling being done by the railway project. All in all the level of  the river bed has increased by 3-4m after the GLOF.

A makeshift road has come up on the right bank and leads to the new IRCON railway bridge being constructed next to the existing one.

Praful Rao
Kalimpong district
Darjeeling-Sikkim Himalaya
savethehills@gmail.com
9475033744

Photographic record of the impact of 04Oct2023 GLOF between Sangkalang and Toong ( North Sikkim) -18Nov2023.

The main road (NH310A) from Mangan to Chungthang (29kms) is blocked near Naga and the bridge at Toong has been swept away, as such now the only road to Chungthang is as shown in RED below which is 40kms long and takes double the time (ie 2hrs).
We made this trip in the early hours of 18Nov2023, leaving Dzongu at 4.30am so that we could spend the whole day covering Chungthang and its vicinity (that will be covered in the subsequent blog).
This blog only records the GLOF disaster at Naga, Ritchu and Toong villages in the Teesta valley, in Mangan, North Sikkim and on NH310A.

The alternate route to Chungthang
Prior to starting a steep climb, one encounters this bridge (27 31 33.5 N 88 31 40.6) Elev 483m/1564', over the pristine and beautiful Kanaka river. See Praveen's drone image below.

Thereafter, the road snakes up in a series of 45 bends at the bottom of the hill and climbs to an altitude of almost 7000'. At places the road is very narrow, hewn out of bare rock with the road edge perilously close..an accident here would mean a fall into a gorge several thousand feet deep and sure death.
This is definitely not a road suitable for heavy vehicles and traffic, being steep, narrow at places and even dangerous.

The army does not allow their vehicles to ply on this route.
After driving on this route for an hour plus we came across areas in the Teesta valley and opposite hill which showed the scars of the GLOF and dam burst on 04Oct2023.

Destruction in Ritchu and Naga village (27.548536N 88.643017E), Mangan district.

Drone images by Praveen of affected areas around Naga village (Mangan district), North Sikkim are given below:

Telephoto images of the same area are below

These photos were taken from (27 32 58.9 N 88 37 48.3 E). There was a lot of haze in the atmosphere hence the discoloration in the photos.
As per Phurkit Lepcha of Shipgyer (village enroute to Chungthang), whom we interviewed - these landslides in the village of Ritchu or Bong (in Toong-Naga GP, Mangan district) did not take place during the GLOF (04Oct) but took place gradually on the 05Oct2023 and thereafter. She expressed apprehension about the survival of these areas in the next year.

I spoke to Dusung Lepcha (31yrs), at Toong village a little later who said that almost the whole village of Ritchu was severely damaged and the destruction at Naga was also immense.

GLOF impact at Toong village (27 33 3.3 N 88 38 38.8 E), 1351m.
We decided to cover the damage at Toong village while on our way upto to Chungthang since it was still  early in the morning.
The road to Toong, itself is badly damaged with a major landslide and several large cracks on the road.
We arrived at Toong after crossing the large Theeng tunnel on NH310A.

Toong lies in the Teesta valley on NH310A or the highway connecting Mangan to Chungthang.
As per locals, the GLOF hit Toong at around 12.30am on 04Oct2023 and took down the bridge at that time. They said villages further downstream ie Ritchu and Naga had also been badly damaged but the only way to get there was crossing the river on a small bamboo bridge on foot.
Sikkim Police had a check post here which was abandoned and lay hanging near the river's edge.

Sikkim Police check post, destroyed by the GLOF on 04Oct2023 lies deserted at Toong.

Drone image (by Praveen) of the destroyed bridge across the Teesta at Toong.  This bridge on NH310A which is more suitable for heavy traffic, connected Mangan (North Sikkim district HQ.) to Chungthang and other areas in North Sikkim.
A local person I spoke to here said that they had lost a lot here and was also not sure of the plight of hundreds of workers who were working on a defense road across the bridge.
Again, there is a frantic effort to rebuild this bridge and to repair the damaged areas of NH310A before the monsoons since the other roadway is definitely not suitable.

Close - up of the destroyed bridge across the Teesta at Toong. The bridge was taken down by the GLOF and dam burst on 04Oct2023. Now one has to cross the Teesta on the tiny bamboo bridge to reach villages across the river.

My thanks to all those we spoke to and all those who helped.

Praful Rao
Kalimpong district
Darjeeling -Sikkim Himalaya
savethehills@gmail.com
9475033744
with
Praveen Chhetri
Junkeri Studio
Kalimpong
junkeristudio@gmail.com
9733185815