Amazing storm activity in the Bay of Bengal in Oct2020

 Although we had minimal rain thus far in Oct 2020, the Bay of Bengal saw a cauldron of activity with numerous storms forming and moving towards peninsular India giving record breaking rainfall in Hyderabad.

 

Earlier, we reported and tracked these storms regularly in this blog in a series called 'STH Stormwatch' but now since we use a WhatsApp group (Hazard Alerts) to disburse information on storms we have discontinued the series.
However, in the interest of recording some of these storms and tremendous activity that took place in the Bay of Bengal I am placing a collage of images and information on the subject most of which we used in 'Hazard Alerts'.
To a lay person like me, I was surprised to find that many of the weather systems in the Bay which affected us had there genesis in massive tropical storms which brewed up in the Pacific and swept across Indo-China. The remnants of these storms intensified in the Bay of Bengal or the Arabian sea.

 Weather chart of that time and satellite imagery of the activity in the Bay of Bengal is placed below:

 

Almost the same scenario was repeated around 20Oct except that the depression which formed off the coast of Odisha/Andhra Pradesh tracked NNE and gave heavy rain to the north eastern states and Bangladesh

 

As I write Typhoon 'SAUDEL' has formed in the South China Sea and will again move westwards and by the next week MAY form yet another low pressure in the Bay

Praful Rao,
Kalimpong district
Darjeeling-Sikkim Himalaya

Rainfall data of some towns in the Darjeeling - Sikkim Himalaya (SEP2020)

  

Heavy rain on saturated soil, compounded by human interference did give us more than our share of landslides in Sep2020.
They are documented here ( 1,  2,  3  )

Praful Rao with Shreya Gurung
Kalimpong district
Darjeelilng-Sikkim Himalaya

Arubotay - a village under threat of extinction from Landslides

Till yesterday, neither I nor anyone had heard of a tiny, obscure village called ARUBOTAY (which literally translates into 'Place of Plum Trees'). It is located in Majua GP, Block Office Bijanbari of Darjeeling district and if it doesn't grow plums, what it does grow is thousands of tons of squash.
Yes! agriculture is the mainstay and livelihood of people in Arubotay - that, along with tourism.
A few days ago I received a call from a friend asking me to visit the village and check the landslide situation there. I did that with STH member Ms Shreya Gurung and Mr Christopher Lepcha of Anugyalaya, a Darjeeling based Roman Catholic NGO.

A report:

1. Location : 27.01843N 088.14789E. Elevation: 1356m

2. Brief history of the landslide
I talked to several people of Arubotay who told me that the initial cracks and fissures had appeared on the hillock during the Sikkim earthquake of 18Sep2011 but many remarked their area was stable even during the mega-disaster of Oct 1968.
Thereafter, the region had remained more or less unscathed during the many intervening years . In 2020 however, the cracks had started 'growing' as early as July following heavy rain. One must note that there is also a fast flowing mountain river (Chota Rangit) below the Sacred Heart School, on the eastern flank of the hill. 
3. Landslide time and date:
The major landslide on the eastern face of the Arubotay ridge line and near the Sacred Heart School occurred at around 11.30pm on 23Sep2020, thereafter it continued on 24/25 Sep2020, when most of the instability and sinking in the village occurred. The landslide continues to be active even now.

Other data on the slide
a. Probable cause : Heavy rain and also erosion by mountain stream on the eastern flank
b. Size : Very large
c. Damage to property etc:
   i. The Sacred Heart School at Arubotay is being demolished since it is unsafe.
  ii. Around 26 homes totally damaged and 10 homes partially damaged
  iii. Loss of farmland - around 20 acres.
  iv. Road communication from Maneybhanjyang to Jorethang (Sikkim) has been cut
d. In all probability most of those who have lost their homes will have to be relocated as the mitigating or controlling the landslide appears impossible.

4. Rainfall data

Detailed rainfall records of our region are available in the STH blog. Day wise rainfall record of Sep2020 will be published in a week.

4. About Sacred Heart School
The new Sacred Heart School building donated by a Luxemburg NGO was inaugurated in 2011 and was run by the Roman Catholic Diocesan trust at Arubotay. The school was functional from much earlier and had 57 students, mostly from around the area, enrolled in 2020.
The building is being DEMOLISHED today.

Update 1
On 10Oct2020, the District Magistrate, Darjeeling accompanied by the GTA Chairman (seen above), visited the ARUBOTAY landslide area and among other things discussed the possible relocation of affected people. We also know that the GSI will be send their officials for a study of the area in a few days.
Update 2 (25Oct)
Two geologists from GSI visited the area around mid Oct2020 and have filed their report to the Darjeeling district administration, based on which the BDO Pulbazar has issued a notice for relocation of the residents of Arubotay. 

Report by Praful Rao and Shreya Gurung
SaveTheHills

Our thanks to the community of Arubotay for their time and help during our visit yesterday and my sincere gratitude to Bishop Stephen Lepcha for his initiative and help.

The Landslides of September end (20-23Sep) 2020

The above rainfall followed the formation of a LOW pressure area in Bay of Bengal around the 20Sep

21Sep2020 images

In the morning, we had a report in 'Hazard Alerts' our WA gp of extremely heavy rainfall on NH 10 and very soon this image of the flooded bridge (Coordinates 26.9832971E 088.417920N) at RAMBI (Kalimpong) was also posted.👇
Rambi was a small, sleepy town known mostly for the local mushroom production till recently- the construction of a dam (TLDP III) and the IRCON Sevoke-Rangpo Broad Gauge railway tunnel work have added prominence to the place.

Almost simultaneously reports of Mirik (Darjeeling district) experiencing torrential downpours came in and this image showing an ☝ area of Mirik town (coordinates 26.8853° N, 88.1828° E) near the lake was posted. It resembles a flooded place in the plains.

22Sep2020 images

Damage on National Highway (NH)10

SETI Jhora landslide (Coordinates 26.93946N 088.44148E, Elvn 233m)

This ☝ gaping hole on NH10 was due to toe erosion by the Teesta river on 22Sep2020 at Seti Jhora . This spot has always been a major maintenance challenge on NH10 and has been responsible for several fatalities in the recent past.

Sign diverting highway traffic put up at Teesta after landslides blocked the NH10 at 29th mile 👇 on 22Sep2020.

29Mile Landslide (Coordinates 27.01435N 088.43594E, Elvn275m)

The scene was in fact worse in the plains of North Bengal 👇 as can be seen in the image from Cooch Behar (26.323921N89.451088E)

My thanks to all those who contributed the photos, reports etc via WhatsApp and in our group (Hazard Alerts) for us to maintain a record of the event for posterity,

Praful Rao
Kalimpong district
Darjeeling-Sikkim Himalaya

A picture which is our shame : a spring in Kalimpong

 As is known, springs all over the Himalayas are fast drying up and I have been involved in several attempts to rejuvenate springs in Kalimpong in the past (see 1 and 2).
It is therefore shocking to see the condition of many of springs from which so many draw their drinking water, this is just one example.

Praful Rao,
Kalimpong district
Darjeeling Sikkim Himalayas

Landslide Report 3 (Kalimpong) - Sep2020

Continuing with the landslide surveys (See Report 1 and Report 2 in this blog)  around Kalimpong town, on 09Sep2020, we went to the north eastern sector of Kalimpong along Reshi Road upto ALGARAH. This road is of strategic importance to India since much of the logistics for the Indian army in East Sikkim (opposite Doklam) goes thru this road. Also in case of NH10 being blocked, this road, via Lava/Gorubathan serves as the alternate route to Siliguri.
Regarding the survey:

• Besides the landslide/subsidence zones mentioned below, what was very evident was the serious deterioration in the condition of the Kalimpong -Algarah section of Reshi road with numerous sinking areas visible on many parts of the road, where another heavy shower or two could result in collapse of the road at multiple places.
• What should be also noted here is that the entire region has many natural springs and jhoras which during heavy rain causes a lot of erosion and landslides in the area.
  
• STH has recorded the extreme rainfall events of AUGUST 2020 and their effects in earlier posts (see 1 and 2). Further the rainfall of August 2020 is also available in this blog. All the landslides recorded below were the result rainfall during the extreme rainfall events.
  

GHATEY KHOLA subsidence

Coordinates: 27° 4'42.00"N, 88°29'50.88"E
Size of subsidence of road : approx 45m in length
During periods of intense rain, Ghatey Khola is notorious for causing landslides in this area since the runoff from the entire populated areas at the crest of the hill finds its way into this drain.
14th Mile sinking zones
The 14th mile sinking areas have been featured in this blog numerous times (see 1 and 2) and are one of the oldest landslide zones in Kalimpong. During the heavy rains of August 2020, these areas were re-activated at almost the same locations causing large portions of the Kalimpong- Algarah road (Reshi Road) to subside.
No other damage to farmland or infrastructure was observed.

Sinking areas of Algarah town

Algarah town is approx 15 kms NE of Kalimpong and has a long history of landslides. I had visited the area some years ago and marked out the sinking areas (above). WIth less rainfall in the past few years, the landslide and sinking zones had also diminished. This year with the intense rains that we have had, the hotspots have re-emerged and perhaps the most crucial one is the one in LAMA WARD which is located in the centre of Algarah town.

Coordinates: 27.1172° N, 88.5837° E
Landslide at HART spring, Dr Graham's Homes, Kalimpong

Coordinates: 27° 4'56.22"N, 88°29'48.48"E 

Photo credits: Ms Shreya Gurung

Praful Rao,
Kalimpong district
Darjeeling- Sikkim Himalaya