Wednesday, December 13, 2023

BBC covers what the Indian National Media missed: The 04Oct2023 GLOF disaster in the Teesta valley

The BBC has today covered the 04Oct2023 GLOF disaster in the Teesta valley here and although the report by Cherylann Mollan, Mumbai has many glitches and errors, I welcome BBC's coverage merely because the National Media has covered it too sketchily or missed it out altogether and the Central and State Governments of Sikkim and W Bengal seem to think the GLOF incident was too insignificant, affecting too few to be bothered about.
Of the many errors in the report, I can point out a few glaring ones:

  • The 04Oct2023 disaster has somehow been named the 'Sikkim flood disaster' which precludes large downstream areas in Kalimpong district (W Bengal) which were also badly affected by the GLOF. This has been made worse by W Bengal government not even considering the event, a disaster.
  • In all probability, what triggered the GLOF was a large landslide or an avalanche and NOT a cloud burst as mentioned by the BBC. Read here
  • The GLOF which started from South Lhonak Lake (elevation approx 17,300') late in the night of 03Oct2023, wrecked many areas around Lachen but the first major town (not nearby village) it devastated was Chungthang (elevation 5,500') approximately 62km downstream and where the Sikkim Urja Stage III 1200MW dam was located. The dam was destroyed by the GLOF which hit Chungthang at 12.35am on 04Oct2023.
    What remains of the 1200MW SIkkim Urja StageIII dam at Chungthang (Photo date: 18Nov2023)

We were in North Sikkim between 17-19Nov2023 and our reports on the devastation in Chungthang town and its vicinity may be read here
Drone photo of devastation in Chungthang town (Photo date:18Nov2023)

I totally agree with Mathew Payne's (the School of Geography, Geology and the Environment at the University of Leicester) statement in the BBC article:

"This catastrophe is a stark reminder of the escalating challenges faced by the verdant Himalayan regions and the increasing magnitude of flooding events necessitates resilient infrastructure capable of tolerating climate-induced excessive rainfall"

which is why we emailed our report and recommendations on the 'Teesta valley GLOF disaster'  to the NDMA and SDMA's of Sikkim and W Bengal on 10Nov2023. The recommendations are essentially short term, aimed at tackling the Monsoons of 2024 which are just 3 months away.

We are yet to receive any reply to our report.

My thanks to BBC for this report on the 04Oct2023 Teesta Valley GLOF disaster.

Praful Rao
Kalimpong district
Darjeeling-Sikkim Himalaya

Thursday, December 7, 2023

Side effects of the GLOF disaster - a trucker's strike in Kalimpong (04Dev2023)

One of the major impacts of the GLOF of 04Oct2023 was its effect on road communications in the lower parts of the Teesta valley that is, on NH10 which connects Gangtok to Siliguri.

About NH10

NH10 is an arterial road, vital for the nation’s security; it is the lifeline for the border state of Sikkim and for Kalimpong district in W Bengal.

Of the 114km distance between Siliguri and Gangtok approximately 92 kms of NH10 lies in mountainous terrain and for much of this distance, the highway winds itself along the banks of the Teesta river. Several large dams have now been built on the Teesta between Chungthang (Sikkim) and Coronation bridge (W Bengal) and many more are planned. The proximity of the river to the highway and the dam activity in this area has undoubtedly contributed to the instability on NH10. The 44.9km IRCON/NFR single lane railway project between Sevoke and Rangpo which has 85% of the distance in tunnels also runs close to NH10 along the valley. This is also creating problems with the excavations from the tunnels and sludge affecting traffic.

This area receives approx 2500-3000mm of rainfall annually and has a lot of landslide activity as such there are many 'hotspots' or large and troublesome landslide areas which routinely disrupt traffic during the monsoons both in the 38km Sikkim section (from Rangpo to Gangtok) and the much longer (62km) W Bengal section (Rangpo to Coronation bridge). The entire region is in earthquake zone IV.
Normally, approx 3500-4000 vehicles ply on NH10 each day from Sikkim, Kalimpong to Siliguri.

The W Bengal section of NH10 is being maintained by the PWD (W Bengal) except for a small portion between Teesta Bazar and Geil Khola which is with NHIDCL. Maintenance of the 28km part in Sikkim from Rangpo to Ranipul is again with NHIDCL

Source: NHIDCL
Current problems   
The GLOF of 04Oct2023 shredded many parts of NH10 and for some time the Kalimpong - Melli section of the highway and the Kalimpong to 27th mile sections were closed due to damage.

Drone photo of NH10 opposite Melli bazar, on 10Oct2023 which had been eroded away by the GLOF
Part of NH10 towards Sikkim from Teesta bazar after the GLOF on 10Oct2023
Part of particularly troublesome part (between Teesta bazar and Geil khola) of NH10 on 18Oct2023. 'A' is Geil Khola which was severely impacted by the GLOF and 'B' is Likhu Bhir landslide area which has been reactivated by the GLOF.

Vehicular traffic quickly resumed on the Teesta - Gangtok section of NH10 and we could report on the impact of the GLOF at Melli and Bhalukhola on 10Oct2023. The Teesta to Coronation bridge section required more time and was only opened for light vehicles (4 wheelers) and between 6am-6pm on 21Oct2023.

On 04Dec2023 truckers from Kalimpong supported by truck unions from Sikkim and also minibus operators called an indefinite strike alleging long delays in repairing the Teesta - Coronation bridge section of the highway. See map below:

* ABCF is the normal NH10 route (in the mountains) for all vehicles . Now this route is only OPEN for light vehicles. On this road, the Siliguri - Gangtok distance is 114km and takes approx 4hrs.
* Section CF is closed for 6 wheeler trucks and buses and other heavy vehicles.
* Because of the CF closure, heavy vehicles from Gangtok and Kalimpong have to detour thru ABCDEF route ie drive thru Kalimpong town, to Lava & Gorubathan which is 228km and takes approx 7 hrs
* Otherwise heavy vehicles have to follow the route shown in blue (241km) ie ABDEF route which again takes 7 hours plus.
Heavy vehicular movements disrupt traffic as such they are only permitted to ply at night thru urban areas, so I met a truck driver from Sikkim enroute to Siliguri, taking a nap at 10.00am on the roadside, because he had a 7hr drive ahead in the night.
NH717A is under construction and is not available to traffic.
A smaller alternate route from Kalimpong across Relli river then thru Samthar and Panbu and Kalijhora is available for light vehicles. However, this route is not suitable for heavy traffic and is at places desolate.
Lastly, a major problem with the alternate routing thru NH717A and the current Lava - Gorubathan routing is that this area receives almost 4000mm rainfall annually, has severe thundershowers during the monsoons and has a number of large landslide zones such as that in Nimbong.
Video of heavy night time traffic thru Pedong bazar courtesy Amod Pradhan
Damaged culvert at 11th mile Kalimpong due to movement of heavy trucks from Sikkim and Kalimpong to Siliguri.

Luckily, the strike was quickly called off with the District Administration assuring the striking transporters that the Teesta - Coronation section would be opened to heavy vehicles and buses from 10Dec2023.

In all this, the plight of truckers and bus operators who have to do a grueling 7-9hr drive from Gangtok to Siliguri is understandable - it is a tough and tiring drive, mostly along mountain roads.

Freight charges of a truck from Siliguri to Kalimpong have gone up from Rs 8,000/- to roughly double that ie Rs 15,000/- and the drivers take two days to complete a round trip.

On the other hand, the caution on the part of the district administration is also very understandable. The Teesta bazar to Sevoke section of NH10 has always been a particularly vulnerable area with numerous 'hotspots' and the GLOF has only made these places weaker. Opening NH10 to full traffic in haste and without any restrictions may expose travelers along the highway to dangerous and weak areas and we have already witnessed a number of accidents along NH10 recently and even some fatalities.

Praful Rao
Kalimpong district
Darjeeling-Sikkim Himalaya

Friday, December 1, 2023

Photographic record of the impact of 04Oct2023 GLOF on NHPC assets at SIngtam, Sikkim

BALUATAR, SINGTAM (27 15 1.8 N  88 27 34.1 E)

While returning from our visit to North Sikkim on 19Nov2023, we stopped by at Baluatar, Singtam to check the impact of the GLOF on the large NHPC complex there. It consists of the NHPC Stage V (Dikchu dam) power station, the Office of CEO, LANCO Teesta Hydro Electric Project, quarters for NHPC officers and personnel, a Kendriya Vidyalaya school, hospital and shopping complex .

View of the damage from NH10.
The damage to the assets has been huge with the bridge connecting the opposite bank at Baluatar washed away:
The whole area was deserted so we could not check when this area was hit by the GLOF, their experience or ascertain what was damaged except that which was immediately visible to us:
Damaged machinery outside the Stage V Power Station.

The raw power of nature is evident from these steel rods which have been bent and torn off. From photographs on the internet, there was a playground here and a lot of trees and greenery. The GLOF has swiped away everything and dumped almost 10 feet of sludge/sand  here.
Damaged electrical components of NHPC Stage VI dam complex at Baluatar
What appears to be a workshop covered with tons of sludge. A bus lies partially buried in the debris.
A structure excavated from approx 12 feet of sludge at the NHPC Stage VI complex.


NHPC TEESTA STAGE VI Hydro Electric Project Barrage at Sirwani, SINGTAM             (27 14 34.9 N  88 28 37.8 E)

The barrage, with what appears to be ruins of the bridge (see map) which was swept down by the GLOF

Literally every crevice and nook along the path of the GLOF has been filled up with millions of tree stumps. The destruction of forests by the GLOF should be quantified to know how much was lost to the floods.
This is the STAGE VI dam at Sirwani, SIngtam on 19Nov2023.

Praful Rao
Kalimpong district
Darjeeling - Sikkim Himalaya


Praveen Chhetri
Junkeri Studios,

Sunday, November 26, 2023

Photographic record of the impact of 04Oct2023 GLOF at Chungthang (North Sikkim) and its vicinity.

Chungthang (Lat 27 36 13.3 N Long 88 38 43.5 E, Elevation:1612.5m) is a small town (population around 4000) in North Sikkim located at the confluence of Lachen Chu ('Chu' means 'Water' in Tibetan) and Lachung Chu. It was also where the Sikkim Urja (Teesta III) dam, a 1200MW, 60 M high Concrete Faced Rockfill Dam (CFRD) was built - it was commissioned in Feb 2017. The dam was the largest run of the river project in the region and the power house was located downstream at Singhik village.
Sikkim Power Investment Corporation Limited (SPICL), a 100% wholly owned public limited company of Government of Sikkim, is the holding company of the project.
The growth of Chungthang between 2006 and 2020 is shown below:

In this regard, quoting from The Sikkim Tourism Development Corporation (STDC) website: 'With the recent hydropower development in the area, the landscape of Chungthang is changing rapidly and is becoming a major settlement in North Sikkim.'
The glacial lake outburst flood (GLOF) from South Lhonak glacier in the late hours of 03Oct2023, released a massive volume of water along Lachen Chu which deluged and engulfed almost the whole of Chungthang at around 12.30am on 04Oct2023. It took down the double lane concrete bridge at Chungthang after sweeping away at least 3 bridges towards Lachen and one bridge across the Lachung Chu.
Amidst the rain, roar and rumble of the river and pitch dark conditions no one is precisely sure when the Teesta III dam collapsed but it did so sometime during the night. It was only on the next day that everyone in Chungthang became aware of the horror and scale of devastation.
The GLOF and the dam collapse caused an unprecedented disaster all along Teesta river valley which SaveTheHills has been documenting since 04Oct2023.
We were in Chungthang for the entire day on 18Nov2023 and talked to many affected people while photographing the disaster - besides just being awed at the raw and vicious power of nature.

What remains of Sikkim Urja (Teesta III), 1200MW dam

Drone image from Chungthang town looking down stream.
The magnitude of nature's forces involved is evident from the giant boulder which has been hoisted to that height and parked in a slot.
Drone image of the dam looking upstream; Chungthang town is in the distant with Lachen Chu on the left and Lachung Chu on the right. The extent of damage is visible even from far.
Satellite image of the dam

This was where Sikkim Urja (Teesta III) dam had its entire office setup. The GM's office and other residential quarters were also here. The surging waters swept away all and left behind some trash and gigantic boulders.
Gigantic rock formations have emerged after the GLOF gouged out all the earth on top (which now form the sand and sludge deposits downstream). The massive boulder clogging up a dam structure can be seen in the background.
Parts and machinery from the Stage III dam now litter the river bed at Chungthang.

The 'GLOF Only' areas. 

By this we mean, areas upstream along Lachen Chu river where the dam burst did not have any impact and the destruction was caused solely by the GLOF from South Lhonak lake.
It was surprising (and scary) to see the amount of damage which had been caused by the GLOF alone. In the distant one can see the ITBP colony where the road to Lachen seen on the right ends.
The damage caused by only the GLOF from South Lhonak lake is huge as can be seen.This drone image reveals the scouring of the river bed caused by the violent waters just a few kilometers towards Lachen from Chungthang.
The impact on Lachen Chu river bed by the GLOF approx 2 km north of Chungthang is seen here. The road to Lachen is only upto the ITBP colony seen in the distant.
Close up of the damage caused by the GLOF alone. A bridge to Lachen has been torn down here (27 36 47.4 N 88 37 47.2 E), further north 2 more bridges have been destroyed by the GLOF, numerous power pylons and towers have been damaged. Army personnel in areas around Lachen reported strong vibrations during the event.
This is where the road to Lachen ends (27 36 42.7 N  88 37 51.4 E) Elev 1705m (Drone image).

Impact on Government assets

Sikkim Government assets located towards the southern tip of Chungthang town were severely damaged by the GLOF
The Legal cell building at Chungthang on 18Nov2023
The SIB office at Chungthang.
The shredded Police Station (Thana) at Chungthang is on the right. A huge truck has been neatly shoved into an office in the thana by the GLOF as if someone had parked it inside. The Chunthang Fire department building, Sikkim Tourism Department guest house has also been extensively damaged in this area.
ITBP shacks along the Lachung Chu which were buried by the backflow from the GLOF. This river was otherwise not affected by the event. Notice this river has turned green as it is winters now - surprisingly, the Lachen Chu is still loaded with silt and brownish. A bridge further up was destroyed by the backflow.
The Chungthang playground and stadium which were deluged by the GLOF.
The army lost a lot of assets  in this area - fortunately no life was lost.
A rifle rack from the Sikkim Police Station (Thana) with the weapons swept away by the swirling waters, at the dam site.
This, along with the loss of army assets adds another dimension to the safety of our riverine areas and even dams.

Chungthang town

The GLOF of 04Oct2023, left the tiny town of Chungthang on its death throes. The midnight floods affected almost every part of the town and the only sounds audible, when we visited Chungthang on 18Nov2023, were the grinding and clanking of heavy machinery as the residents tried to excavate their homes and get their lives back together.
More than 54 RCC buildings and homes were damaged by the floods, many smaller wooden homes and shacks were simply swept away. Also what was lost were countless Buddhist artifacts, monuments and antiques which every affected home had and which the floods snatched away.
A school was destroyed in the centre of town.
Drone image of Chungthang town on 18Nov2023, showing the extent of damage by the GLOF.
Satellite image of the above area.
On the left, Lachen Chu or the Teesta river flows downstream and a Bailey bridge has been  constructed by the army engineers on 16Nov2023 at 'A' above which allows some sort normalcy of movement and supplies coming into the town.
Drone image showing the devastation wrought by the GLOF in areas adjacent to the river bank.
Drone image from the road to Lachen showing erosion of the river bank adjacent to Chungthang town. In the foreground are areas where there were several army installations.
Satellite image of the playground area of Chungthang town.
The town on 18Nov2023. Massive rocks are strewn all over and 10-15 feet of sludge plasters much of the town area.
An army truck has been parked inside a room by the GLOF. Notice the level to which the flood waters reached.
Chungthang on 18Nov2023.
The gilded dome of Gurudwara Nanak Lama Sahib is seen in the background.
The Gurudwara and its staff provided and continues to provide extraordinary service to the denizens of Chungthang. The ground floor of the Gurudwara was inundated by the GLOF and the staff evacuated temporarily to return quickly and provide food and shelter to thousands of people. While we were in Chungthang, 70 odd homeless people were staying in the complex and everyday 3 - 4000 meals were being provided to anyone who wanted food.
Photo of 05Oct2023 showing removal of sludge and debris in front of the Gurudwara at Chunthang (Photo credit: Lhendup Lepcha)
Officials of the Sikkim Government conducting a survey on losses to homes and property at Chungthang. They said government engineers were also testing the structural stability of damaged buildings. With much of the town in ruins, this process will take some time to complete.

The Rivers and the Environment

Photo of 05Oct2023 shows a gap where there was a double lane concrete bridge over the Teesta at Chungthang. It was taken down by the GLOF. (Photo credit: Lhendup Lepcha).
A tiny bamboo bridge over the Teesta for ferrying men and material before the current Bailey bridge (below) was completed by army engineers.
Photo of 18Nov2023 shows a bridge across the same spot, which army engineers put across the Teesta on 16Nov2023..
The armed forces have always taken a lead role in helping out in all disasters and so it was in Chungthang in Oct2023 where they were instrumental in providing warning, evacuating tourists and saving lives and the civilians in Chungthang I talked to gratefully acknowledged this.
Photo of 07Oct2023 showing army/BRO/ITBP/ and other people trying to put a ropeway across the Teesta at Chungthang.The river was again in spate and there was light rain as such the effort was abandoned.(Photo credit: Lhendup Lepcha)
Heavy road construction machines and men of the BRO working on the road towards Lachen.
(Photo credit: Lhendup Lepcha)

The completion of repair of the Chungthang - Lachen road may take anywhere from 3 - 6 months and right now Lachen is connected to Zema and Thangu only by a temporary bridge. The people of these areas will require extensive help to face the harsh winters ahead.

All in all, I am amazed at the scale and ferocity of nature's revenge.

My humble thanks to all who helped.

Praful Rao
Kalimpong district
Darjeeling-Sikkim Himalaya


Praveen Chhetri
Junkeri Studios,