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

Impact of the Teesta Valley GLOF: Photo feature on Krishnagram - a sinking zone in the Teesta Bazar (21-22Jul2024)

While we (Junkeri Studio with SaveTheHills) have featured this area as a part of numerous surveys of GLOF affected areas done in Oct2023, both of us visited the Krishnagram area of Teesta bazar again between 21-22July2024.

Bhasuwa (27 03 41.7 N 88 25 29.2 E, Elevn 248m) as the name implies, is a sinking area but the rate of subsidence increased dramatically after the Oct 2023 GLOF raised the Teesta river levels by 4-5m. The river now flows very close to Bhasuwa and as such the erosion at the base of the mountain and subsidence has increased. The place was renamed Krishnagram.

While reporters, politicians and engineers visit the destruction along the Darjeeling-Kalimpong road at Krishnagram, not many are aware of the plight of villagers living directly above the area. Here, a paralyzed elder brother lies on the floor of Mrs Ganga Sarki's (age 55yrs) home. She reports a numbing sense of desperation with nowhere to go, as her home falls apart.(Photo: Praveen)

A woman stands in her home which is rapidly being destroyed as a part of the hill at Krishnagram slowly slides into the Teesta river. Residents report being scared of the nights and of the terrifying sounds they hear as the cracks widen and nails come off wooden beams.(Photo Praveen)

Villagers evacuating to safer areas with whatever moveable property they can salvage as the cracks on the ground and walls become bigger.
Around 15 homes are affected in the village directly above the road at Krishnagram (Photo: Praveen)

The Community Hall at Krishnagram (earlier called Bhasuwa) on 21Jul2024. This hall was used as a Relief Centre, with many families staying here during the GLOF disaster of 04Oct2023. 

The buckled up and destroyed interior of the Community Hall at Krishnagram on 21Jul2024. This hall had 9 families living here during and after the GLOF disaster of Oct2023.

A resident in the Community Hall which was used as a Relief Centre on 10Oct2023 when we visited Teesta bazar. The floor was severely cracked even then but the subsidence of the ground has increased now with the river running wild during the monsoons.

The severely depressed and slumping part of the Darjeeling-Kalimpong road at Krishnagram (earlier Bhasuwa).The Community Hall is on the left while the home of Mr Tika Karki is on the right side of vehicle. Tika Karki has abandoned his home and lives with relatives in the bazar while his home itself has nearly keeled over in the last 24hrs or so.

The Darjeeling-Kalimpong road was closed on 22July2024 afternoon, after the cracks on the road increased significantly and a large tree here fell, due to the ground instability.(Photo: Praveen)

Another new unstable area is this spot (27 03 38.7 N 88 25 29.7 E Elevn 239m) on the Darjeeling-Kalimpong road, in close vicinity of the Teesta police station - again due to elevated levels of the river (post GLOF). (Photo taken from inside vehicle hence the streaks)

Updated DRONE images of Krishnagram (Bhasuwa)

The image shows the most severely affected area of Krishnagram at Teesta bazar. The road leads to Darjeeling (to the right) as well as the business center of Teesta bazar which is also affected by the river.

The image shows subsiding areas of Krishnagram above the Darjeeling-Kalimpong road.

The entire sinking area of Krishnagram, with the Teesta river continuously eroding the base of the hill.

Praful Rao along with Praveen Chhetri
SaveTheHills,
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

Was there a cloud burst in Sikkim on 03Oct2023?

The media is howling about a cloud burst that occurred in North Sikkim around the 03Oct2023 and which triggered the GLOF (Glacial Lake Outburst Flood) at South Lhonak lake, which led to the terrifying devastation in Sikkim and Kalimpong district on 04Oct 2023.

To get to the truth of the matter let us first see what is a cloud burst:
As per IMD
'If 100mm rainfall is received at a station in one hour, the rain event is termed as cloud burst.'

Placed below is a map and the rainfall data of North Sikkim (and Gangtok) and of Darjeeling and Kalimpong for the period 01Oct to 04Oct2023.

What is apparent is that Darjeeling and Kalimpong received far more rain than North Sikkim during this period and to support this are placed the Infra Red cloud images of 03Oct2023. Sikkim

It is highly unlikely that the type of clouding seen in the vicinity of Lhonak glacier would trigger a cloud burst since such high intensity rain is normally associated with convective clouding and cumulonimbus (CB) clouds which generate a distinct white signature in IR satellite images.
What are cumulonimbus (CB) clouds and how do they appear on IR satellite images?

How CB clouds appear on satellite imagery

There is no doubt that a GLOF did occur at South Lhonak glacier on 03/04Oct2023 between midnight and around 1am on 04Oct2023 - satellite imagery and reports from people at Lachen confirm this.
However, the widely held belief that a cloudburst triggered the GLOF is probably incorrect and maybe ascribed to media loosely calling any 'heavy rain' event a 'cloud burst' just as many issues these days are conveniently labelled under the banner 'climate change' without any verification.

So if a cloudburst did not trigger the GLOF, just what did?

That is a question which has still not been answered.

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

Rainfall data of June 2023 of some towns in the Darjeeling -Sikkim Himalaya (along with images of landslides which occurred)

Cyclone 'BiparJoy' (09Jun-16Jun2023)
Formed as a 'low' in the Arabian sea in the first week of Jun2023 and intensified into a cyclone. We watched the storm closely and reported on the movement and forecast track of the storm extensively in our What's App group 'Hazard Alerts'.

 

June Weather
The first 10 days of June were HOT and DRY and the monsoon was delayed by several days.

 

 

The rainy spells for Jun2023 came in 3 spells ie on 11Jun, 17Jun and the last week of June2023.
Taking an example of KALIMPONG rainfall, please note:

• Kalimpong had the highest rainfall among the 4 towns. Kurseong normally has the highest rain. All this rainfall was concentrated in 17 days, 13 days being bone dry.
  
  
• Rainfall on FIVE DAYS ie 11, 17, 26, 27, 28 Jun2023 amounted to 431mm which is equal to 88.8% of the monthly rainfall.
  
  
• And what happened was that this rainfall came in short, intense bursts and so the 431mm of rain must have come down with several hours - NOT days.
  See previous blogs on this here1 and here2
  
  
  

This rainfall, as expected resulted in numerous landslides.

 

 

We will be uploading rainfall data of the previous months in due course.
Thanking all those who contributed the above images in our What's App group 'Hazard Alerts', regretfully the coordinates of the places are not available.

Praful Rao
Kalimpong district,
Darjeeling- Sikkim Himalaya