Landslide update 1Aug22

 Landslides along NH10

1. Berrick Dara - NH10

2. 29th Mile - NH10

Approx. Latitude Longitude given in the image below

Rainfall data of Kalimpong:
1Aug22 - 42.4mm
31Jul22 - 52.6

Video Credits: KTV 

Shreya Gurung

Kalimpong District
Darjeeling Sikkim Himalaya

Rainfall data of Jul2022 of some towns in the Darjeeling - Sikkim Himalaya

As per IMD, the southwesterly wind flow occurring over most parts of India and Indian Seas gives rise to southwest monsoon over India from June to September. The typical rainfall pattern over the Darjeeling-Sikkim Himalaya is shown below:

July is the month when our rainfall normally peaks, with the rains gradually decreasing thereafter.
The rainfall record of July2022 (day wise) of some towns of this region is  tabulated below:

You will notice that we have added rainfall data of
a. Mangzing (a remote village in Pokhriabong GP, Gorubathan block, Kalimpong district)
b. Bijanbari (Relling GP, Pulbazar block, Darjeeling district)
in our effort to map the rainfall of this region.
What is clearly evident is that the rainfall of July 2022 for many parts of the hilly regions of North Bengal and Sikkim was significantly below the normal monthly rainfall (615.8mm). Also for the first time in many years, Kalimpong rainfall exceeded that of Darjeeling.
What is also noticeable from the graph (Fig 1) is the towns mentioned had significantly higher rainfall in June than July which is an anomaly.

Fig1

July 2022 began with a large deficit in rainfall in the Sub Himalayan W Bengal and Sikkim regions however, the rains picked up a little in the third week of July. The paddy crop which is normally planted in July in rain flooded fields never happened in many places (Fig2).

 Fig 2

There was also very little activity in the Bay of Bengal and Pacific Ocean in this entire period  with hardly any typhoons forming in Pacific or low pressure areas in the Bay. A low which formed in Bay on 10July along with the rainfall deficiency is shown in Fig3:

 Fig3

Rainfall departures for July2022 for W Bengal and Sikkim are given below (Fig4)

Fig4

Rainfall was also deficient in South Bengal (Fig5)

 

 (Fig5)

Despite the deficit in rainfall, there were landslides especially along roads and NH10

Landslide at Reshi checkpost on NH717A (below Pedong (Kalimpong district) on 25July 2022.

Shreya Gurung
&
Praful Rao

Kalimpong district
Darjeeling Sikkim Himalaya

SaveTheHills activities: July 2022

Awareness programs
Raising awareness about Landslide Hazards and other related issues has been one of our most important roles and we have held or participated in hundreds of seminars and workshops at a variety of platforms from the grassroots to national programs.
In July 2022 we participated in two such programs: the Ban Mahotsav program held in Kalimpong Town Hall by the West Bengal Govt Department of Forests and the other organized by Anugyalaya DDSSS in a small village school in Pubung, Gorubathan block, Kalimpong district.

 

Pubung, on the other hand is a remote village in Pokhriabong GP, In Kalimpong district. There
Shreya and I participated in awareness program with some 30 odd school children and villagers in a small wooden village school and talked about rainfall patterns, importance of data keeping and community action during disasters. We distributed
a. Landslide Reporting Forms
b. A checklist in Nepali for action prior to heavy rain or major storms
c. A documentary film on Landslides (dubbed in Nepali) made for primary school children by ISRO and SaveTheHills
d. 5 large silpaulin (plastic) sheets for use by the community in case of evacuation during landslides

Landslide Early Warning project with IIT Delhi at a landslide prone location in Kalimpong
The DST has funded a landslide early warning project with IIT Delhi for monitoring landslides in Kalimpong.The project will implement a pilot prototype for a non-intrusive opto-electronic method of detecting and warning people about a landslide. This is expected to be a significant method of warning and alerting people about an impending landslide.

• The project site is around Dumsi Pakha, a densely populated landslide prone area in Kalimpong Municipality  where the opto –electronic sensors would be installed and monitors would be placed on the opposite hillside.
•  The project which would be operational before the monsoons of 2023 is led by Prof Subrat Kar of the Dept of Electrical Engg, IIT Delhi and will last for 2yrs.
  

SaveTheHills, a Kalimpong based NGO is the local partner.

Praful Rao
Kalimpong district
Darjeeling-Sikkim Himalaya

 

Measuring rainfall manually - Challenges and Dilemmas

Rainfall is being measured at thousands of places in India using the Symons Rainfall Gauge. SaveTheHills has been recording rainfall for the past 10 years or so in this region. We have also distributed these rainfall gauges at many places around Darjeeling-Kalimpong district and have been receiving data from these locations. The daily rainfall data for each month is collected and published on our blog for everyone to use. Yet now we are faced with a dilemma on the accuracy of the data we have published. Recently we received an extremely high rainfall record (329mm in 24hrs) from Mangzing (Gorubathan), Kalimpong where we had given one rainfall gauge. Such extreme rainfall would have triggered landslides yet none were reported. This made us curious as to the accuracy of the rainfall gauge. We performed a small experiment taking three rainfall gauges, one used by us (Borosil) the other used in Mangzing (Exsil), and the third used in a school (Plastic 10mm container). The results were alarming.

Attached below is the video explaining our experiment and the results. Have a look.

Shreya Gurung
Praful Rao

Darjeeling District
Darjeeling-Sikkim Himalaya

Rainfall data of Jun2022 of some towns in the Darjeeling -Sikkim Himalaya

The month of June got us in Kalimpong and Darjeeling scratching our heads about the whereabouts of monsoons 2022. While the North-Eastern states of Assam, Meghalaya, Sikkim, and Tripura were affected by extreme rainfall, Kalimpong and Darjeeling had a rather quiet and dry month. Siliguri and its vicinity experienced heavy showers in the second half of June. The link about an event to note in Siliguri on 20Jun22 is attached here.

East and North Sikkim received extremely heavy rainfall triggering many landslides that affected the major roads and caused fatalities. Landslides in various parts of Sikkim have resulted in 8 fatalities and numerous casualties from 14Jun22 to 27Jun22, economic losses unknown.

Source: Pakyong Sikkim

Area: East Sikkim

 

Source: Voice of Sikkim

Area: Jholungay, South Sikkim

Landslides in Kalimpong and Darjeeling occurred on NH10 and NH55 between 12Jun22 and 28Jun22, causing major traffic dislocations and damage to the roads.

 

Source: Hazard Alert WA group

Area: Between Bagpool and Kalijhora, NH10

A detailed description of the landslides have been collated here.

Shreya Gurung

Ankit Mankar

Darjeeling District

Darjeeling-Sikkim Himalaya

At last, some signs of activity in the Northern Arabian Sea and the Pacific Ocean (27Jun2022)

When queried, a senior meteorologist had this explanation: