Saturday, July 13, 2024

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.



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
Yukta Acharya

Kalimpong district
Darjeeling-Sikkim Himalaya

Friday, June 28, 2024

Memorandum for urgent action on the Teesta Valley disaster 2024, submitted by SaveTheHils (STH) and Darjeeling Himalaya Initiative (DHI) on 27Jun2024

A submerged Darjeeling-Kalimpong road and stranded vehicle on 13Jun2024 at Teesta bazar, Kalimpong district

During our numerous visits in Oct/Nov2023 to many parts of the Teesta valley following the GLOF disaster of 03/04Oct2023 (photo records of which are in this blog),
 it was plain to see the magnitude of the catastrophe and the limited time available for any major restoration/mitigation work before the arrival of the 2024 summer monsoons.
With just 6 months time to set the house in order and with the General Elections looming up in April 2024,
 we anticipated that major engineering works required to keep populated areas in the valley safe and repairs to NH10 would never be possible. As such, even though we had not surveyed areas beyond DIKCHU, we emailed our report and recommendations (consisting mostly of short term measures which were doable in the time available) to the Chairman, NDMA, Chairpersons of Sikkim and W Bengal SDMA's and a host of other senior government officials and political parties. This was done, jointly by SaveTheHills (STH) and the Darjeeling Himalaya Initiative (DHI) between 10-13Nov2023 and the entire report and recommendations was published on this blog on 22Nov2023

Our opening statement in the report is reproduced below and now seems ironically prophetic:

  •   'We need an expert team to visit these areas and advise us the course of action to be taken in the limited time we have before the next monsoons.
  •   We should focus on building the resilience of communities in the flood affected areas while continuing with the recovery and reconstruction process, since many of our populated areas in the Teesta Valley in Sikkim and W Bengal will again be affected during the Monsoons 2024.
  •   Time is of essence'

Since we received no acknowledgement or replies to the Report/Recommendation emailed, STH sent a reminder on 17Feb2024 to the Home Affairs (Disaster Management) Department in (Centralized Public Grievance Redress and Monitoring System). The report is reproduced below:

'On 04Oct2023, the entire Teesta Valley, including areas in Sikkim as well as W Bengal was devastated by a Glacial Lake Outburst Flood (GLOF) from South Lhonak glacier in North Sikkim and the collapse of a 1200MW dam at Chungthang (Sikkim). Both DHI and STH has been following the disaster and its impact and the devastation has been recorded extensively in the STH blog with reports, photographs and maps.
On 10Nov2023, we emailed a report of the devastation to the NDMA and SSDMAs of Sikkim and W. Bengal suggesting some short term measures which were necessary to mitigate the impact of the summer monsoons in 2024 (
Essentially the report noted that
a. The Teesta river bed had risen by as much as 3-4m all along the valley due to sediment deposits during the flood and as such many populated areas were exposed to flood risk from a river whose path was now unpredictable.
b. The floods had caused extensive damage to government and private infrastructure along the valley and no major dams on the Teesta river, north of the Teesta Low Dam Project IV at Kalijhora were functional.
c. The short term measures suggested were

• Improved early warning and alerting mechanisms in the valley

• Better preparedness of relief and evacuation centres

• Capacity building and raising awareness among affected locals

• Rehabilitation/relocation of the many people who had lost everything during the flood

• Road safety along NH10 which suffered extensive damage.

Now that the pre- monsoon season is almost here, we request that these and other pertinent issues relating to saving lives and property may be looked into urgently.'

This report was acknowledged by an Additional Secretary of the DM Division but
has only a cryptic remark saying 'Suggestions are noted' and the case was closed.

Nothing happened thereafter.
Now 6 months have passed and the monsoons are here and we face it with very little disaster mitigation work being done or better preparedness, anywhere in the Teesta valley.

Around 13Jun2024 and for several days thereafter, rainfall in the catchment areas in North Sikkim resulted in the river swelling up and engulfing parts of Teesta and Melli bazar and the Kalimpong to Darjeeling road. The Likhu Bhir section of NH10 which is 7km (aerial distance) from Kalimpong is again giving continuous problems and approximately 1200 tourists were rescued from north Sikkim where a newly constructed bridge at Sangkalang was swept away and 9 people died in landslides at Mangan(district HQ of North Sikkim).

The CM of Sikkim Mr PS Golay made a hurried visit to Delhi and met the PM, Finance Minister, Home Minister and Jal Shakti Minister and has requested for funds as well as experts to help manage the disaster in Sikkim.
We have not heard anything from the Govt of W Bengal even though the most troublesome   50km of NH10 (out of the 90 km distance from Sevoke to Gangtok) lies within W Bengal and mostly in Kalimpong district as are many low lying populated areas in the Teesta valley.

In view of the developing situation and with three months of rains still ahead of us, STH and DHI have again emailed a letter to the Chairman NDMA, MInister in Charge SDMA W Bengal, MP Darjeeling and several other political heads.
The Memorandum submitted yesterday (27Jun2024) is reproduced below:

Praful Rao
Kalimpong district
Darjeeling- SIkkim Himalaya

Monday, May 13, 2024

The Teesta Valley GLOF disaster of Oct2023 in WMO 'State of the Climate in Asia 2023' report

The above report has been released by WMO (World Meteorological Organization) on 23Apr2024 and contains a comprehensive account of the climate and extreme events in Asia in 2023:
The Teesta Valley GLOF disaster has also been mentioned prominently in the report (page 18) and it vindicates our stand on it - that it was the largest GLOF disaster in the Himalayas in the recent past and YET it hardly received any attention from the national media or the state governments and the centre.
After the WMO report however, several national level e- papers have carried the story:

Praful Rao
Kalimpong district
Darjeeling Sikkim Himalaya

Wednesday, May 8, 2024

Normal Rainfall stats for Sub-Himalayan West Bengal (SHWB) and Sikkim updated by IMD Gangtok.

 The Rainfall Normals for SHWB and Sikkim have been revised by IMD. The OLD one (below)

has been updated and the NEW Rainfall Normals are placed here:

Significant points to note are:

  • The period of observation has decreased from 1951 to 1971 to 2000 ie a 20 year decline.
  • There is an overall decrease in the TOTAL rainfall by 169.1mm ie from 2708.9mm to 2539.8mm
  • There is a significant decrease (325.5mm) in the rainfall for the winter and pre-monsoon periods so we will have more drought like conditions during this period.
  • There is a significant increase (254.9mm) in the rainfall for the post monsoon period.
  • Rainfall during the monsoon period has also decreased by 116.7mm. 

Source: IMD Gangtok (Sikkim)

Praful Rao
Kalimpong district
Darjeeling-Sikkim Himalaya

Sunday, April 14, 2024

Our adverse weather early warning work on What'sApp groups in the Darjeeling- SIkkim region: Thunderstorms of 11/12Apr2024 in Kalimpong

After the Teesta Valley GLOF of 04Oct2023, our region has been extraordinarily dry, with the erratic western disturbance activity in the winter months, robbing us of all our winter rain. In Kalimpong we had the first showers after Oct2023, between 19 & 27Mar2024 where we clocked 112.6mm. Thereafter, it has been dry with forest fires again starting in the Teesta Valley.
With regard to early warnings on adverse weather events and disbursement of information on landslides, road blocks etc, SaveTheHills has been running several very active and large What'sApp groups in the Darjeeling-Sikkim region called 'Hazard Alerts or HA' for many years now and the following cloud image on approaching adverse weather was posted in the group on 11Apr2024:

This image was posted on 'Hazard Alerts' WhatsApp group at 1.31pm on 11Apr2024 along with lightning warnings from the IMD 'Damini' (lightning warning) app. Shortly after this was done, the first storm hit our region at around 2.30pm. Wind speeds in gusts reached upto 58kmph.

This storm died down momentarily at around 4.30pm only to pick up again quickly. The following cloud image along with NOWCASTs from IMD were posted to members in the 'Hazard Alerts' What'sApp groups.
Warning posted at 5.36pm to our WhatsApp groups alerting them about another storm which was approaching.
Subsequent cloud images which show the progress of the storm from 6.45pm to 10.45pm on 11April2024

The thunderstorm which hit Kalimpong at 2.30pm on 11April2024, raged right thru the night and only ceased at around 8.00am on 12Apil2024. Surprisingly, we had only 2mm of rain however strong, gusty, westerly winds from Nepal along with lightning prevailed for more than 12hrs. The graphical analysis of the windspeed from our Davis Vantage Pro AWS is placed below:

Though there were no casualties or damage from the storm, what was unusual was its duration considering there was no major weather system (such as a depression/cyclone) near by.
Also what is possible today is to get reliable and accurate information of such weather events in advance and to disburse the same quickly to a large number of people. We have been doing this regularly in WhatsApp since Jun 2016.

Praful Rao
Kalimpong district
Darjeeling-Sikkim Himalaya

Impact of the Oct 2023 Teesta Valley GLOF on road communications at Likhu Bhir on NH10 ( Kalimpong district, 13-14Apr2024)

On what is becoming a familiar story, NH10 is closed for maintenance work and again at Likhu Bhir - an old landslide, who's ghosts were resurrected by the GLOF of 04Oct2023 and is causing headaches to the District Admin & PWD and nightmares to those using the highway. It is closed again this weekend, seven days after it was shut down for repair last week.

Images of maintenance work taking place on NH10 at Likhu Bhir on 13Apr2024
My thanks to Mr Mukesh Sharma, reporter from Kalimpong for sharing these images with STH

Praful Rao
Kalimpong district
Darjeeling Sikkim Himalaya

Sunday, April 7, 2024

Impact of the Oct 2023 Teesta Valley GLOF on road communications - the continuing nightmare at Pedong and Toong

Map showing trouble spots at Pedong and Toong

Traffic bottle necks at PEDONG
Pedong (27.1594° N, 88.6157° E) is a small town in Kalimpong district and is nowhere near the Teesta valley yet the impact of the Oct 2023 GLOF is being felt daily by the residents of the town.
The Teesta valley GLOF reactivated a dormant landslide at Likhu Bhir which continues to pose a problem for traffic along NH10 so the Kalimpong District Administration has again closed that section of the highway for the weekend as per this travel advisory:

As a result the entire heavy vehicular traffic to / from Sikkim to the plains of North Bengal is routing thru Kalimpong and Pedong causing huge traffic jams in Pedong. The vehicles have also damaged water pipelines causing disruptions in water supply in the town and damaged other infrastructure since the roads are narrow and were never intended to handle such heavy, continuous traffic.

Traffic jam at Pedong
Likhu Bhir landslides on NH10 (Nov2023)

TOONG bridge
The bridge at Toong was vital for communications to North Sikkim and when the GLOF took it down, traffic had to be routed thru a longer and more dangerous route which we took while going to Chungthang in Nov2023.
The locals had constructed a wooden bridge over the Teesta river in Feb2024 (see below) which was being used by light vehicles.
Wooden bridge at Toong in Feb2024
However, the recent rains in the area resulted in the bridge being damaged (see video)
Since the alternate route is longer and much more cumbersome, locals at once got down to repairing the damage (see images of 06Apr2024 below)

I don't think this bridge will hold out for much longer now that the pre- monsoon showers have started over our region...which leaves us in a rather precarious position with regard to all the GLOF damaged road communications in our region - a question which I asked back in Nov2023...

                               How do we manage in the Monsoons of 2024?

My thanks to all friends and HA members from Pedong, North Sikkim who made this report possible. Please stay safe.

Praful Rao
Kalimpong district
Darjeeling Sikkim Himalaya

Wednesday, April 3, 2024

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

Saturday, March 30, 2024

The National Highway 10 (NH10 - Siliguri to Gangtok) maintenance problem (post GLOF) begins in Mar2024

NH10 and Likhu Bhir in 2017 & 2023

MoRTH website on NH10
reads as follows:
'The highway starting from Indo / Bangladesh Border connecting Fulbari Siliguri in the State of West Bengal connecting Sivok, Kalimpang near N.H-10 and terminating at Gangtok in the State of Sikkim'. 52kms of the highway is in Sikkim, the remaining 65.97kms being in W Bengal.
Further to our earlier report on National Highway 10 (NH10), the recent rains in our region caused landslides along parts of NH10 which resulted in road blockages and traffic jams and as such the Kalimpong District Administration has closed parts of NH10 for traffic as per the letter below:

Prolonged closure of NH10 dates
Road closures for several hours on NH10 due to landslips, erosion and rockfalls etc are commonplace and take place almost daily during the monsoons. Prolonged closure dates of the highway in the recent past are as follows:-
* In 2007 and 11Jun2010 at HaatiSurey, near Coronation bridge – blocked for a week.
* 26Jun-03Jul2015 due to landslide at SetiJhora (near TLDP IV)
* 14-15Jan 2016 due to landslide at BhoteyBhir (near Rangpo)
* 06Jul2019 for almost a week at Seti Jhora

Despite several alternate routes now being available (see map below), NH10 remains the shortest distance with the least gradient changes and is the quickest way to commute from Sikkim and Kalimpong to SIliguri and the plains of North Bengal - however, it may not be the safest route anymore.

NH10 and alternate routes

DATA ON NH10 (and the alternate routes from Gangtok and Kalimpong to Siliguri)

Distances - Siliguri to Gangtok
Via NH10 - 114kms out of which approx 90kms is in mountainous terrain. Approx 60kms from Singtam to Sevoke is along the banks of the Teesta river.
a. Alternate route 1 (via Pakyong- Reshi-Algarah-Lava-Sevoke-Siliguri) - 241kms
b. Alternate route 2 (via Rangpo-Chitrey-Kalimpong-Algarah-Lava-Sevoke-Siliguri)  - 205kms

Distances- Kalimpong to Siliguri  
Via NH10 - 67kms
a. Alternate route 1 (via Ghoom -Kurseong) - 99kms
b. Alternate route 2 (via Algarah-Lava- Gorubathan-Sevoke) - 132kms
c. Alternate route 3 (across Relli river- Samthar- Panbu-Kalijhora-Sevoke)

It is estimated that approximately 3000 vehicles use the NH10 daily when permitted.

Images of landslide and traffic snarls in that part of the road
Rockfall at Likhu Bhir after rains on 23Mar2024
Traffic jam at Chitrey (Teesta) due to rock fall at Likhu Bhir, 23Nov2024
Traffic jam at Likhu Bhir on 24Jan2024 at around 6pm


As we have reported earlier, Likhu Bhir is an old landslide which was dormant for many years until the GLOF of 04Oct2023 reactivated it.
File photo from July2019

Also as reported, the Teesta river bed has risen by almost 4m all along the valley due to the silt and sand deposits brought down by the GLOF, which makes NH10 much more prone to subsidence/erosion (the TLDP III and IV dam activities and the IRCON tunnelling having contributed their share to making sections of NH10 more prone to subsidence, rockfalls and landslides)

Rainfall (at Kalimpong) from 19Mar to 23Mar2024
It was surprising that very moderate rainfall, after almost 4 months of complete drought could trigger so much instability in the Likhu Bhir area.
Recently, I met a geomorphologist who said that the Oct 2023 Teesta Valley GLOF was the biggest such event in the Himalayas in the recent past. I believe him entirely.

My thanks to our WhatsApp group 'HA' members who's photos I have used :)

Praful Rao
Kalimpong district
Darjeeling-Sikkim Himalaya