Thursday, August 25, 2016

Changes in rainfall pattern (Darjeeling Sikkim Himalaya) : Aug2016

In July and August are the peak months for the SW monsoons in this region, in Sept the rainfall should decline and in Oct the monsoons normally exit the sub-continent....

Praful Rao,
Dist Darjeeling

Sunday, August 21, 2016

STH Stormwatch : The Movement of a Storm in 24hrs (20-21Aug2016)

As I write, this storm is very active over south Bengal where there is continuous but moderate rain, in Kalimpong we have thundershowers.
Update on the above storm  (22Aug2016)
The thunderstorm continued well into the night; rainfall data is given below. One person died in a fatal landslide at Samrik Paani, Pokhriabong, Darjeeling last night and NH10 which is an arterial highway linking Siliguri with Gangtok was blocked at Likhu Bhir (see below) and 10 other places.

Rainfall data of 21Aug2016 (in mm)
21Aug2016 started off as a hot sunny day. It clouded up in the afternoon and in Kalimpong it rained from approx 1530h till about 2130h.
Kalimpong : 45
Kurseong : 95.8
Siliguri : 18
Mal Bazar : 95
Gangtok : 14.8
Darjeeling : 74.6

Praful Rao,
Dist Darjeeling

Wednesday, August 17, 2016

Update on landslide dam in North Sikkim (17Aug2016) : Satellite images from NRSC/ISRO

All images post by Dr SS Porwal on 'Landslide Management' WA group. I have sharpened the images and increased sizes in PS.
  • Water level in the dam seem to be fluctuating, it had dropped 7' yesterday morning but increased by 5' later in the day.
  •  GSI estimates the landslide, which is said to be a rock avalanche to be 1km long and width 572m. As per reports from the site, the slide is still active with large rocks still sliding down occasionally.
  • The landslide dam has been breached and the outflow from the dam and water levels in the pondage are being monitored continuously.
Praful Rao,

Tuesday, August 16, 2016

STH stormwatch (16Aug2016) : Well marked low pressure in Bay is likely to intensify

Update (17Aug2016)
The 'well marked low' has intensified into a depression and is likely to move northwest wards.
Another low is expected in the same area around the 20Aug2016.

Praful Rao,
Dist Darjeeling

Sunday, August 14, 2016

Update on Landslide Dam in North Sikkim (14Aug2016) :more images


1. No casualties so far.
2. Administration has started 'miking' along some areas of NH10 which might be affected if the landslide dam bursts or overflows, this entails passing the message on vehicle borne PA systems. The important thing here is to avoid creating panic.
3. NDRF has been dispatched to the area.
4.Geologists and Disaster Management officials will survey area today.
5. Info from locals - the Kanaka river has already overflown the dam (not verified)

Praful Rao,
Dist Darjeeling

Saturday, August 13, 2016

Landslide dam in North Sikkim on Kanaka RIver (13Aug 2016)

From our side, we are in touch with representatives of the Govt both at the Centre and States and members of  the community in Dzongu, North Sikkim and continuously exchanging information.
Luckily, there is no rain in this region and those likely to be immediately impacted have been evacuated.

Praful Rao,
Dist Darjeeling

Rainfall data of July2016 for the Darjeeling Sikkim Himalayas and the landslide activity of the month

July 2016 was an extraordinary month for Darjeeling district and North Bengal :-
a. All 3 major towns (Darjeeling, Kalimpong and Kurseong) of the district received more than the monthly average with Kurseong getting approx 3 times the amount.
b. But is in the plains that rainfall was heaviest. Siliguri received 354mm of rain on 24Jul2016 and much of Jalpaiguri district saw some of the highest rainfall in recent memory (Slide 9). The hills of Bhutan also received very heavy rains (Slide 8)resulting in most of the rivers emanating there, flooding the plains of Dooars and Jalpaiguri district.
c. There were many, many landslides (Slide 10) all over Darjeeling district but two killed people. On 09Jul2016, two people were crushed to death when a vehicle (Slide 3) they were travelling in, was hit by a falling boulder at Sweti Jhora on National Highway (NH) 10 (linking Siliguri to Gangtok). Later on 20Jul2016, a whole family of three was wiped out at Finchey Taar, in Lodhoma Darjeeling (Slide 6)  by a landslide following heavy and prolonged rains.
d. On 21Jul2016, the district administration decided to demolish (Slide 7)13 houses on the banks of the Teesta river on NH10 at 29th Mile near Kalimpong. The houses were perilously perched on the banks of the Teesta river and on an area which was known to be subsiding.The occupants had been compensated years ago but were refusing to move.
e. Most of the rain came down in the second half of July when IMD reported the axis of the monsoon trough had shifted close to the foothills (Slide 2). The typical clouding which persisted for much of the month is see on the IR image of 21Jul2016 (Slide 14). IMD also clamped a RED warning for SHWB (Sub-Himalayan W Bengal) and Sikkim for much of the entire month of July2016 and with good reason (Slide 5).
f. The roads and highways suffered tremendous damage. NH10 had a large number of bottlenecks which make driving from Siliguri towards and into the mountains both difficult and dangerous (Slides 3 and 11). NH55 or the route from Darjeeling to Siliguri was equally precarious with the main Rohini route closing down  (Slide 12)on 26July2016 and remain so till date.
Other routes like the Kalimpong-Algarah road fared no better with large chunks of it falling off (Slide 13) or being buried under debris (Slide 4).

Praful Rao,
Dist Darjeeling

Wednesday, August 10, 2016

STH stormwatch (10Aug2016) : Depression in the Bay of Bengal intensifies into a deep depression and moves inland

Aug2016 has seen the development of at least 2 low pressure areas in the first week, in the Bay of Bengal. Both formed off the coast of Odisha and moved inland on an almost northwesterly track.
Extract of 'Inference' of 10Aug2016 (evening) for the depression above is below :-
'The deep depression over south Bangladesh & adjoining West Bengal moved north­
northwestwards during past 3 hours and lay centred at 1430 hours IST of today i.e. 10th August, 2016, over Bangladesh ; neighbourhood with its centre close to Latitude 23.4°N and Longitude 89.1°E, about 60 km east of Krishnanagar (West Bengal),40 Km southeast of Chuadanga (Bangladesh). The system is likely to move slowly north­northwestwards during next 24 hours. Subsequently,it is likely to weaken gradually and move west­northwestwards.'

Praful Rao,
Dist Darjeeling

Monday, August 8, 2016

STH Activities : At the first meeting for formulating a National Strategy for Landslide RIsk Management, NDMA, Delhi

Excerpt from The
NDMA holds meeting on Landslide Risk Management Strategy
The National Disaster Management Authority (NDMA) today called on a meeting to discuss the formulation of a National Landslide Risk Management Strategy. This was the first meeting of the task force of landslide experts created for preparing an effective national strategy for landslide risk management.
The task force consists of six sub-groups specific to different aspects of landslide risk management strategy - generation of user friendly landslide susceptibility maps; development of monitoring and early warning system; awareness generation; capacity building & training; preparation of mountain zone regulations and policies; mitigation of landslides and creation of special purpose vehicle / centre for landslide management.
Inaugurating the meeting, Lt. Gen. N.C. Marwah, Member, NDMA, said the task force may submit its proposals which could be taken up immediately to prepare a national strategy for quick implementation.
Underlining the importance of strengthening the early warning, preparedness, prevention and mitigation efforts, Dr. Saibal Ghosh, Director, Geological Survey of India (GSI) informed that the number of casualties in landslides can be prevented if the country has a detailed and uniform landslide hazard mapping for use of community that takes into account all the elements of risk such as settlements, population, infrastructure, etc.
The meeting also emphasized upon the need to develop landslide Early Warning System (EWS) and integrating the usage of latest technological tools such as wireless sensor networks and web-based GIS interface to ensure that the information reaches the last man on time. A comprehensive plan on capacity building, training of stakeholders and preparation of mountain zone regulations and policies would be other key areas of the strategy.
Prof. R. B. Singh, Delhi University emphasized upon the need for extensive information, education and communication campaigns to create awareness among people about preparedness, do's and don'ts and response. This will lead to active participation of the communities and other stakeholders. With new technologies such as mobile phone apps and online portals easily available, it is easier than ever before to reach out to the youth in schools and colleges, Dr. Singh said.
Scientists, academicians and experts from various Departments, Institutes and State Governments apprised NDMA of the work already done by them in the area of landslide risk mitigation. Advising the States to draw their strategy on landslides in line with the broad framework given by NDMA, the Authority said the Landslide Risk Management Strategy will also incorporate the priority areas as indicated in the Sendai Framework for Disaster Risk Reduction.
The meeting was attended by subject experts from various educational institutions and organisations such as Council for Scientific and Industrial Research (CSIR), Indian Institute of Remote Sensing (IIRS)-ISRO, Uttar Pradesh Remote Sensing Application Centre (UPRSAC), G.B. Pant National Institute of Himalayan Environment and Sustainable Development (GBPNIHE&SD), Defence Terrain Research Laboratory (DTRL)-DRDO and Border Roads Organisation (BRO) apart from senior officials from NDMA.
Landslides affect about 15 percent of India's landmass and cause destruction and losses of varying degrees in at least 22 States and Union Territories.

Praful Rao,
Dist Darjeeling

Comment : Am a part of the Task Force convened for the above purpose.