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

The National Highway 10 (NH10) which connects Siliguri to Gangtok and is the lifeline for Sikkim and Kalimpong district runs along the river valley almost hugging the banks of the river for almost 50 odd km. The monsoons extracted a heavy price for this closeness in Aug2024 - the highway was closed for almost 20 days due to landslides and erosion.

As per the above data:

• Darjeeling, Kalimpong (in West Bengal), Gangtok, Mangan, Damthang (in Sikkim) recd almost normal rainfall.
• Kalimpong, Siliguri, Jhallong, Alipur Duar (W Bengal) and Dentam in Sikkim recd went deficient in rainfall.
• Most of the rainfall occurred in the first half of the month (see below).
  
  This was undoubtedly due to the low pressure areas and depressions which formed in the Bay of Bengal and moved towards western India, which resulted in surplus rainfall in those parts towards the end of Aug2024 (see above).
  
  

  
  

  

  Major Landslide
  A major landslide occurred in Sikkim on 20Aug2024 at Dipu Dara, just above NHPC Stage V Power House at Baluatar.
  We have covered the entire incident in our previous blog report
  

  
  Documentation of a part of the above report was supported by Royal Enfield, as part of their Social Mission Initiative
  
  
  Praful Rao
  SaveTheHills
  savethehills@gmail.com
  9475033744
  
  

  
  
  
  
  

 

Rainfall data of Oct 2022 of some town in the Darjeeling - Sikkim Himalaya

 

As can be seen from the above table, Kalimpong, Darjeeling, South and West Sikkim had deficient rainfall while East and North Sikkim had excess rain. The plains of north Bengal including Siliguri had more or less normal rainfall.
The rainfall, however was confined to the first half of the month when the monsoons were quite active in the entire country even as the SW monsoons 2022 started withdrawing from the subcontinent. After 15Oct2022 there was no rain.

A series of low pressure areas formed in the Bay, some as remnants of tropical storms from the Pacific.

Remnants of tropical storm 'SONCA' formed a low pressure in the Bay which eventually intensified into Cyclone 'SITRANG' in the Bay of Bengal

SITRANG was the first cyclone to hit Bangladesh after 2017.

Media on Cyclone 'SITRANG' (Indian Express, 25Oct2022):

 Power and telephone links have been largely cut and coastal areas plunged into darkness, officials said.

A tropical storm that lashed Bangladesh left at least 35 people dead and about 8 million without power across the delta nation, officials and news reports said on Tuesday.

The government said about 10,000 homes were damaged and more than 6,000 hectares (15,000 acres) of crops were destroyed. Thousands of fishing projects were also washed away.

 The United News of Bangladesh news agency said about 20,000 people were marooned because of flooding triggered by tidal surges in the southern coastal district of Bhola.

Tropical Storm Sitrang brewed in the Bay of Bengal before turning north toward Bangladesh’s vast coast, prompting authorities to evacuate hundreds of thousands of people to cyclone shelters Monday. Heavy rains battered the country throughout the day, flooding many areas in the coastal regions across southern and southwestern Bangladesh.

Praful Rao
Kalimpong district
Darjeeling Sikkim Himalaya

Rainfall data of Mar 2022 of some towns in the Darjeeling- Sikkim Himalaya

 As has been the noticeable trend, rainfall was severely deficient in Darjeeling and Kalimpong districts whereas all of Sikkim had much better rain in Mar2022

Forecasts for two depressions maturing into cyclonic storms in the Bay in Mar2022 proved erroneous and the storms remained as depressions.

With deficient rain our region remained very dry resulting in a number of forest and other fires.

Praful Rao and Ms Shreya Gurung of STH
Kalimpong district
Darjeeling-Sikkim Himalaya

NOVEMBER RAIN of the region (2020)

We had a few storms in the Bay of Bengal (see previous posts) but they affected the southern states only and our region remained absolutely dry with no rain in the entire region except for North Sikkim receiving rain on

18Nov (in mm)
Mangan -  24.2, Chungtang-  5.8, Shipgyer-  5.2, Singhik-  19.4
19Nov (in mm)
Mangan-  4.2, Shipgyer-  8, Singhik-  3.6

Praful Rao with Ms Shreya Gurung,
Kalimpong district
Darjeeling-Sikkim Himalaya

Rainfall data of some town in the Darjeeling- Sikkim Himalayas (Oct2020) - GOING RED ALL THE WAY

 The OCT2020 saw some really hectic weather activity in the Bay of Bengal, the Darjeeling-Sikkim Himalaya escaped this and except for North Sikkim which recorded above average rainfall, all other towns had deficient rainfall.

The rainfall stats from IMD are shown below:-

The sudden and sharp change from 'Large Surplus' rainfall in Sep2020 to 'Deficient' rainfall in Oct2020 is seen below:

With the numerous storms in the Bay of Bengal in Oct 2020, the withdrawal of the SW Monsoons from this region was delayed.

Collection and tabulation of rainfall data : Ms Shreya Gurung

Praful Rao
Kalimpong district,
Darjeeling- Sikkim Himalaya

Rainfall data of Darjeeling Sikkim Himalayas - August 2019

Rainfall data of Siliguri, Gangtok (East Sikkim), Dentam (W Sikkim) and Damthang (S Sikkim) are from IMD.

There were no major landslide events in August 2019 in our region.
My thanks to all my friends who helped in compiling the above rainfall data.

Praful Rao,
Kalimpong district,
Darjeeling - Sikkim Himalaya

Rainfall data of Mar2019 for the Darjeeling-Sikkim Himalaya

Praful Rao
Kalimpong district
Darjeeling - Sikkim Himalaya

Rainfall data of Darjeeling -Sikkim Jan 2019

Jan 2019 rain (in mm)
Darjeeling : NIL
Kalimpong : NIL
Kurseong : NIL
North Sikkim: 19mm


Praful Rao,
Kalimpong district,
Darjeeling Sikkim Himalaya

Rainfall data Darjeeling-Sikkim Himalaya (April/May2018)

April2018

May2018

• We could not obtain Sikkim rainfall data after April2018
• Both Sikkim and SHWB (Sub Himalayan WB) were running deficient in rainfall in the entire pre-monsoon period.
  Praful Rao,
  Kalimpong district,
  Darjeeling - Sikkim Himalaya

Rainfall data of Darjeeling- Sikkim Himalaya (August 2017)

From 'The Hindu' (15Sep2017) : Recurving cyclones dried August rains

 

A strange pattern of tropical cyclones (TC) in the Western Pacific appear to be the reason for the drying up of monsoon rains in August across India.
The India Meteorological Department (IMD) had predicted normal monsoon rains in August, typically the second most bountiful monsoon month after July.
During the monsoon months, cyclones in the Western Pacific move westwards towards India and aid rain-bearing systems over the sub-continent. But during some years they ‘recurve’, or start to swing north-east, and do not give as much of a push to the rains as they do in the good monsoon years
Read further here

The delay in putting up this report as well as the incomplete data in the Sikkim report is regretted but was totally beyond our control, due the ban on internet in this region and the ongoing political agitation.

Praful Rao,
Kalimpong district
Darjeeling-Sikkim Himalaya

 

Rainfall data (Darjeeling -Sikkim Himalaya) - August 2016

A number of low pressure areas developed in the Bay of Bengal in Aug 2016 but we received little rain from these systems and went deficient in rainfall from the first week till the end of the month. Early in Aug 2016, what has been described as local event dumped 95mm of rain on the Chungthang-Mangan highway at Lantha khola, it caused a major landslide which breached the road.
A photo of the same is placed below.

The major event of the month was the Dzongu landslide of 13Aug2016 which took place in North Sikkim and has been covered in an earlier blog

Praful Rao,
Kalimpong,
Dist Darjeeling

Withdrawal of SW Monsoons from this region : 15Oct2015

Though we had a number of low pressure systems and depressions developing in the Bay of Bengal (see blog for details) in 2015, we have had only ONE cyclone (Cyclone Komen) forming in the Bay this year where we normally have around 4-5.
There is much literature available on the internet on the trend in the frequency of cyclonic disturbances in the Bay of Bengal, this is just one such article.


Praful Rao
Kalimpong,
Dist Darjeeling

Rainfall data Darjeeling-Sikkim Sep2015 and monsoon withdrawal.

Sep2015 again saw us getting deficient rainfall even though Kurseong (as always) had higher than normal precipitation.
What is worrisome is the peaking of rainfall (see graph above) on certain dates, which seems to be the established trend in our rainfall pattern now.

Praful Rao,
Kalimpong,
Dist Darjeeling