The link between rainfall intensity and global temperature (from Dave's Landslide Blog)

One of the most interesting aspects of the global landslide database that we maintain at Durham is the way in which it has highlighted the importance of rainfall intensity in the triggering of fatal landslides. Generally speaking, to kill people a landslide needs to move quickly rapid, and rapid landslides appear to be primarily (but note not always) triggered by intense rainfall events (indeed in the reports the term "cloudburst" often crops up). So, a key component of trying to understand the impacts of human-induced global climate change on landslides is the likely nature of changes in rainfall intensity, rather than that of rainfall total. Put another way, it is possible that the average annual rainfall for an area might decrease but the occurrence of landslides increase if the rainfall arrives in more intense bursts.

(For those interested the full article can be read here)

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Comment by Praful Rao

Even though STH does not have accurate data to support the above article, it is true that in 2009 we had high intensity rainfall on 5 occasions (shown in earlier blogs) - and 4 of these "extreme events" caused severe landslides in the Darjeeling district.

Images from Landslide Hazard Workshop at Town Hall, Kalimpong :21Nov2009

A strike in the Darjeeling district on 20Nov2009 , necessitated rescheduling the entire workshop for the next day - luckily for us the venue (Town Hall) was free and so we could go ahead with the workshop - with some changes as 2 resource persons were not available on 21Nov2009.
The resource persons on 21Nov2009 were :-
a) Prof Leszek Starkel
b) Prof Jeta Sankrityayana
c) Dr Vimal Khawas
d) Wg Cdr Praful Rao (retd).

I am glad to tell you that despite all the many hurdles and the last minute changes that were required, the workshop was a success.
I will be posting the outcome document of the workshop in a few days.


Praful Rao

In the next week...

Last year exactly at this time STH conducted a workshop on Landslide Hazards at Southfield College, Darjeeling. I have the proud priviledge of announcing that we are again organizing a workshop on similar lines, this time at Kalimpong. Whereas sceptics (I was also one) may debate the ultimate result of conducting these sessions, I am now convinced that these workshops, meetings and awareness camps have to carry on relentlessly... it is only then that somewhere, sometime the community first and then people in the media and govt circles will start thinking about prevention and the many other aspects of this little known disaster form.

Praful Rao

At the Second India Disaster Congress, Vigyan Bhavan, Delhi

I had the unique privilege of attending the 2nd India Disaster Management Congress at Vigyan Bhavan between 04Nov-06Nov2009 ( those interested on details of the Congress can read it here).

What I am extremely glad to report is that during the question hour of  thematic sessions on "Mass Movements (Landslides and Avalanches)"- Plenary Hall, 05Nov2009, thematic session on "Involving Communities, NGOs in Disaster Management"- Plenary Hall, 05Nov2009  and that on "Early Warning and Disaster Communication" on 06Nov2009 (Hall no 5) I could raise the following issues :-

a) The increase in the incidents and severity of landslides in Darjeeling and the need for a holistic and sustained strategy to manage landslides in the district. ( During thematic session : Landslides)

b) Compensation for land loss (esp to farmers) due to landslides. ( During thematic session : Landslides)

c) Possibility of the Govt machinery issuing "Heavy Rainfall and Landslide Alerts" through SMS broadcasts. ( During thematic session : Early Warning and Disaster Communication )

d) Insurance of land against landslides. ( During thematic session : Communities, NGOs in Disaster Management )

Praful Rao

Comment by Praful Rao
My regrets for not posting more photographs - the security during the meeting often deterred  one from using cameras. However, more photos should be available on the NIDM website.

Documentary film on Landslides

Nine final year students of the Dept of Mass Communication, St Joseph's College, North Point - Darjeeling (which included students from Darjeeling, Sikkim and Bhutan) were here in  Kalimpong on 27Oct2009 - they are working on producing a documentary film on "Landslide Hazards in the Darjeeling district". Besides doing an exhaustive interview on the subject, they discussed the causes and effects of landslides with STH. The documentary is being being made for the  Montage College Film festival at the college on 28Nov2009.

We intend to collaborate with the Mass Communication Dept of the college during the ensuing monsoons with the intention of producing a high quality documentary on landslides

Praful Rao

An invitation for the 2nd India Disaster Management Congress in Delhi (04Nov-06Nov09)

STH (with a lot of help from the affected people of Chibo and Pashyor) had in the first week of Sep2009 submitted a paper to the 2nd India Disaster Management Congress (IDMC) about the vulnerability of  Chibo - Pashyor to landslides and the urgent necessity for a long term solution. The same has been accepted formally as a part of the documentation for the Congress.
As such STH has officially been  invited to the Congress and I will certainly attend the IDMC2.

Praful Rao

Rainfall peaks : 2009

Technically the SW monsoon completes it withdrawal from this part of the world on 12Oct and judging by the fine weather we have been experiencing for the past few days, I just hope it is so.
Placed above is an approximation of the rainfall pattern in 2009, the consequences of which are given in brief below :-

(A) 25-27May2009.
We experienced a direct hit by Cyclone AILA which dumped as much as 350mm of rain in 3 consecutive days. The western parts of Darjeeling district (Kurseong and Darjeeling) suffered the most damage - 27 persons died in landslides and roads, tea gardens and infrastructure sustained immense damage.
(B) 02July2009.
Kalimpong received 112mm of rain in a single day. Even though there was only one death, Nimbong and Pabrintar in Kalimpong subdivision were severely affected by landslides. It took more than a week to restore the Nimbong-Bagrakote road which is the life line for people living in the area.
(C) 15Aug2009.
A single day's rainfall amounted to 152mm. 6 persons died in Kurseong and there was significant damage to houses and infrastructure.
(D) 19Aug2009.
Coming within 4 days of the above rainfall, the 198mm of rain on 19Aug caused immense damage. Chibo/Pashyor remain isolated from Kalimpong as on date (14Oct) with roads and bridges having been washed away by the deluge.
(E) 07/08Oct2009.
36 hrs of rainfall brought in 280mm of rain. However, there was no report of any major damage or death, most probably due to the fact that Sep2009 was largely dry and the moisture content in the earth had decreased significantly.

Detailed reports (with images) on all the above incidents can be found in earlier blogs

Praful Rao

36hrs of hell (06-08Oct2009)

Rainfall data for Darjeeling and Kalimpong for approx 36 hrs(06-08Oct2009)

Darjeeling - 288mm
Kalimpong - 280mm


Average rainfall (last 5 yrs) for Darjeeling district for the month of Oct  : 132mm (source http://imd.gov.in/section/hydro/distrainfall/webrain/wb/darjeeling.txt)

It rained for just about 36hrs and unlike Cyclone AILA, there was no well formed system which was "trackable", nevertheless it dumped close to 300mm of rain (equal to more than double the monthly rainfall) in barely one and half days.
For all of us living here in the affected areas , the 36hrs were as many hrs in hell!
Slide 'A' shows the satellite picture from http://imd.gov.in on 07Oct09 at 3.30am IST
Slide 'B' shows a close up of the same area on 08Oct09 at 5.30am IST

The fact that there were no major landslides this time is perhaps because
a) In Sept09 we had almost 2 weeks of sunshine and as such the moisture content in the soil had reduced considerably.
b) The rainfall lasted for 36hrs only.

Comment by Praful Rao
Annotations on Slide 'A' and 'B' are mine.
Rainfall data source :-
a) Darjeeling ................... Compuset, Darjeeling
b) Kalimpong................... Govt of WB

Why landslides are an unknown disaster form..

• Only 15% of the Indian landmass is affected by landslides and many of the affected areas are in remote inaccessible places.
• Landslides are typically a recurrent form of "small disaster", which gets ignored at the national level in comparison to extreme and extraordinary "high impact" events such as earthquakes.
  Yet the attrition, cumulative loss and impact on development caused by landslides over years often exceeds that caused by the infrequently occurring mega disasters.
  
• Statistics for recorded wrongly. Most often losses due to landslides are attributed to events which trigger them eg losses and deaths between 25-27May2009 in Darjeeling are ascribed to Cyclone AILA and not to landslides.
  This leads to an erroneous and deceptively low loss/damage rates being reported for landslides.
• Govt and media parameters (in India) of judging the severity of landslides are confused and needs to be made exact and precise in order that a landslide can be evaluated correctly.
  As on date govt and media still report the severity of a landslide in terms of the number of houses "fully or partially" damaged or the number of lives lost.
  On 19Aug2009 in Kalimpong landslides, triggered by high intensity rains caused huge damages to roads and infrastructure such as bridges/culverts and caused much loss of farmland. Fortunately no one died.
  Media and govt reports still stuck to reporting the losses in terms of "numbers of houses partially and fully damaged".
  This confused method of assessment leads to an under reporting and incorrect estimation of the scale of the devastation by the hazard.
  
  Praful Rao
  

What took place and what's in the offing...

04-06 Nov2009 (Second India Disaster Management Congress, New Delhi)
STH had submitted an abstract on “Landslide Hazard Case Study: The dire need for a comprehensive, long term solution to the landslide problem at Chibo - Pashyor villages, Kalimpong, District Darjeeling, W Bengal”, under the theme "Mass Movements (Landslides and Avalanches)" for the Second India Disaster Management Congress, at Vigyan Bhavan on the above dates.
I am glad to inform all that it was accepted by the Review Committee of the Congress, as such STH stands officially invited to attend the Congress. I am happy that this gives us an opportunity to highlight our problem at a national forum.20Nov2009
World renowned geomorphologist, Prof Leszek Starkel of the Polish Academy of Sciences will be with us in Kalimpong once again and this time we will be holding a one day workshop here on "Landslide Hazards in the Darjeeling/ Sikkim Himalaya"
I enclose a small writeup on the Professor:-
Prof Leszek Starkel

He was born in 1931, in Wierzbnik, Poland.
He began his scientific career in the Institute of Geography of the Polish Academy of Sciences.
Professor Starkel has been active on the international stage by participating in over 100 congresses and workshops in 37 countries, among them seven IGU congresses and all five congresses of the International Association of Geomorphologists.
In addition to his European work, his field studies have been in Asia, India, Mongolia and China, and his work has been recognized by leading geographical societies in Hungary, Slovakia and Sweden and he is an Honorary Member of the International Union for Quaternary Research.
Also Professor Starkel is noted for his close links with geographers in India through his work on floods and landslides in the Darjeeling Himalaya.
He has been visiting India since 1968 and has been involved in International Bilateral Collaboration of Scientists programme between Polish Academy of Sciences & Indian National Academy of Sciences since the Year 1985.

Praful Rao