Thursday, July 16, 2026

Urban landslides, the silent killer in our midst...


Having seen countless landslides and talked to hundreds of landslide victims in my almost 20 years of working on this hazard, there is lots to be elated about...much has progressed in the study and mitigation of this earlier underrated hazard. 
Yet a common misconception is that a landslide is a massive hill collapsing (which it often is) and thousands dying (rarely happens) and that mitigation of landslides involves lots of complicated engineering which is stupendously costly (which also maybe true).
However, in the midst of all this what we are witnessing with a change of rainfall patterns is that there is a manifold increase in the surface runoff from intense rainfall - simply because there is so much more concrete and asphalt in the mountains today in our urban centers and our drainage system remains abysmal to handle these huge volumes of high velocity water.
So the landslides which have emerged as a big menace in all our mountain urban centres are a human induced smallish slips, which in a densely populated area can kill people.
I am reproducing a report on a landslide which took place in the Kalimpong Municipal area on 13Jul2026:
Landslide Damage Assessment Report
Date of Visit: 15 July 2026
Date of Incident: 13 July 2026
Time of Incident: Approximately 4:30 a.m.
Location of Incident: Ward No. 20, 9th Mile, Kalimpong Municipality, below Rockvale Academy School, Kalimpong


A field visit was conducted to assess the impact of the landslide that occurred on 13 July 2026, understand the condition of the affected households, identify their immediate needs, and observe any continuing risks at the site.
Incident Overview
At approximately 4:30 a.m. on Mon, 13 July 2026, a landslide struck a residential area, affecting two households. One house was completely damaged, while the second sustained partial damage. Fortunately, no casualties or injuries were reported due to the timely response of the affected families and the immediate assistance provided by neighbours and the local community.
Household 1 - Mr. Asta Ratna Bajracharya
Mr. Asta Ratna Bajracharya, aged 60 years, works as a local school transport driver and is the head of a household comprising seven family members. At the time of the incident, however, only Mr. Bajracharya and his 55-year-old wife were present in the house.
According to Mr. Bajracharya, at around 4:30 a.m., they heard an initial loud sound from outside. Assuming it was a tree falling due to the continuous rainfall, they did not immediately suspect any danger. A few moments later, they heard a second, louder sound, which caused them to wake up. As they were getting up, a third and much louder impact occurred when the landslide struck the house.
Mr. Bajracharya explained that the landslide primarily impacted the opposite side of the house from the room where he and his wife were sleeping. This provided them with enough time to react and escape. As the usual exit was no longer accessible, they climbed out through a window. Once outside, they were able to see the extent of the damage caused by the landslide.
The first response was provided by nearby neighbours and members of the local Samaj, who immediately came to assist the couple. Shortly afterwards, personnel from the Fire and Emergency Services arrived at the site. They broke through a section of the damaged wall and assisted in retrieving household belongings that remained trapped inside the house.
The house has been completely damaged and is no longer safe for occupancy. Fortunately, no lives were lost, no livestock was affected, and all-important documents were recovered safely. Mr. Bajracharya and his wife are currently staying in a nearby rented accommodation. They informed that the rental expenses are presently being taken care of through support from the concerned authorities. At present, they do not have any immediate relief needs. Their primary concern is access to a safe and permanent house.
During the discussion, Mr. Bajracharya stated that one of the major contributing factors to the landslide was the poor maintenance of the drainage system. He explained that the drain had frequently become clogged due to indiscriminate dumping of waste. He further shared that he had personally taken the initiative on several occasions to clean the drain and had even installed a signboard requesting people not to dispose of waste in the area. Despite these efforts, waste dumping continued, resulting in blocked drainage and diversion of rainwater towards the slope.
Household 2 - Mr. Sukraj Bajracharya
Mr. Sukraj Bajracharya, aged 86 years, lives with his 81-year-old wife in a household comprising nine family members, including two school-going children. On the day of the incident, seven family members were present in the house.
Mr. Sukraj Bajracharya shared that he usually wakes up early in the morning and was the first to hear the unusual sound outside. Realizing that something was wrong, he immediately alerted the other family members and asked them to move to a safer area of the house. His prompt response ensured that everyone evacuated safely before the situation worsened.
The landslide caused partial damage to the house. Although there was no major structural collapse, a significant amount of mud and debris entered the house, and a portion of the wall had tilted, making the building unsafe for habitation. At the time of the visit, debris was still present inside the house, and some household belongings had yet to be removed.
The family has temporarily shifted to a nearby rented accommodation, where the rental expenses are currently being supported through external assistance. They have also received support from the local Samaj and other individuals. Similar to the first household, they reported no immediate relief needs other than the need for a safe and permanent house.
Mr. Sukraj Bajracharya also expressed the view that poor drainage maintenance and the blockage of drains due to waste accumulation were among the major factors that contributed to the landslide.
Observations
During the site visit, it was observed that the slope above the affected houses remains unstable. Several bamboo clumps on the upper slope were visibly tilted, indicating the possibility of further slope movement if continuous rainfall persists.
Both affected households consistently identified poor drainage maintenance as one of the major contributing factors to the landslide. They stated that drains had frequently become blocked due to indiscriminate waste disposal. In addition, it was observed that construction materials such as stones, pebbles, and aggregates had been stored along sections of the roadside. During periods of heavy rainfall, these materials can obstruct the natural flow of surface runoff, divert water towards vulnerable slopes, and contribute to blockage of drainage channels.
The assessment highlights the importance of regular drain maintenance,
- Report by Stephen Lepcha,
Anugyalaya

Rainfall Data

Notice that we had 3 dry days prior to the landslide occurring on 13July morning and also, the rainfall both in the amount (91.6mm) and intensity (instant peak approx 100mm/hr) was not very high.
I am glad to report that despite the loss to property no one died in this landslide but this blog is replete with  reports of fatal anthropogenic landslides in urban settings and the one which I remember most, is where a mother and her two children lost their lives. It occurred just 5 mins from my home in 2010.
Yet the solution to managing this type of landslide is deceptively simple and does not involve complex engineering or huge costs. Simply put it is:

a. Short term: Manage the water flow; keep our drains clean during the monsoons so that water does not accumulate and cause slope failure. Create quick reaction teams within the community and equip them with power tools to effect a quick rescue.
b. Medium term: During the dry season, repair unstable slopes using bioengineering and other methods so that they are safer during the next monsoons. Repair and enlarge drains and keep our jhoras (natural drains) clean. 
c. Long term: Work on raising awareness among the public and govt officials towards creating a safer environment.

My thanks to Stephen for his report and photos.

Praful Rao
SaveTheHills
savethehills@gmail.com
9475033744



Saturday, June 20, 2026

Extreme weather event and thunderstorms of 18/19Jun2026 in the Darjeeling-Sikkim Himalaya

  Weather and Rainfall data


As can be seen above, the IR satellite image of 08.45pm /18Jun2026 shows a line squall or a line of thunderstorms which had formed in Nepal as a part of Western Disturbances (WD) affecting us. The storms moved eastwards and it started raining at around 9pm in Kalimpong on Thursday ,18Jun2026.
Despite the monsoons having advanced into our region on 10Jun2026, the predominant weather system which affect us so far remain the numerous Western Disturbances which are still moving in from the west and giving quite a lot of rain in the W Himalayas, dust storms and rain in the Delhi region and rain in the eastern HImalayas.
IMD had issued an ORANGE warning for thundershowers
Graphical analysis of the rainfall and wind from 17Jun-19Jun2026 is below:
There was widespread thundershowers in the hill areas of Kalimpong, Darjeeling districts, Sikkim and parts of the plains including the Dooars. Heaviest rainfall was in Champasari (in SIliguri) - 207mm, with Kurseong receiving 193mm precipitation. The rainfall was accompanied with intense lightning and thunder mostly taking place after midnight this morning (19Jun2026), thankfully both the intensity and windspeeds at least in Kalimpong, remained under control.
Detailed rainfall of the region for 17/18/19Jun2026 is tabulated (by IMD) below:

IMPACT of the Extreme Event

The intense thundershowers caused significant damage to infrastructure and roads and at least one fatality.
Landslide in Norbung area of Sittong
Notice for road diversion due to bridge collapse at Mirik
Damaged road near Pagla jhora, Kurseong
Update on 21Jun2026


My grateful thanks to Hazard Alerts (out WhatsApp group) members whose photographs I have used above.

Praful Rao
SaveTheHills
savethehills@gmail.com
9475033744


Thursday, June 4, 2026

Rainfall data of May 2026 of some towns of Sub-Himalayan W Bengal (SHWB) and Sikkim.

May marks the final month of the pre-monsoon season and normally receives 257.5 mm rainfall over the Sub-Himalayan West Bengal (SHWB) and Sikkim region according to IMD (1971–2000 normals). The month is usually characterized by thunderstorms, squalls, hailstorms, and increasing moisture influx from the Bay of Bengal ahead of the southwest monsoon.


May 2026 was a highly variable month, with rainfall distributed unevenly across the region. Some locations experienced rainfall well above the long-term normal, while others remained comparatively dry.

A notable feature was the occurrence of several intense rainfall events between 13–17 May and again around 22–26 May, particularly affecting Sikkim and parts of the Himalayan foothills.
The extraordinary rainfall which took place in Kalimpong on 28May2026 is covered in an earlier blog.

 Wettest Stations
  1. Mangan – 642.3 mm
  2. Gangtok – 584.5 mm
  3. Sevoke – 440.4 mm
  4. Kurseong – 434.2 mm
Driest Stations
  1. Khanitar – 92.4 mm
  2. Darjeeling – 131.2 mm
  3. Kalimpong – 213.0 mm 
Above and Below normals
The IMD normal rainfall for May over SHWB & Sikkim is 257.5 mm. 

Above Normal

Mangan (+149%)
Gangtok (+127%)
Sevoke (+71%)
Kurseong (+69%)
Banarhat (+43%)
Alipurduar (+43%)
Siliguri (+30%)
Damthang (+18%) 

Near Normal 
Neora (−8%) 

Below Normal 
Kalimpong (−17%)
Darjeeling (−49%)
Khanitar (−64%)

Spatial Distribution

Northern Sikkim (see map - Zone 1)

Mangan and Gangtok experienced exceptional rainfall. 

Foothills and the Dooars (see map - Zone 2)

Sevoke, Banarhat, Alipurduar and Siliguri all received abundant rainfall. The foothill belt was particularly active during thunderstorm episodes.

Darjeeling/Kalimpong Hills (see map - Zone 3)

Darjeeling itself was surprisingly dry compared with neighbouring Kurseong and Kalimpong. This highlights the highly localized nature of pre-monsoon convection and terrain-induced rainfall.

Praful Rao
SaveTheHills
savethehills@gmail.com
9475033744

Friday, May 29, 2026

Extreme rainfall event in Kalimpong town on 28May2026 (instant rainfall intensity > 500mm/hr)

Flooded street in Kalimpong town at around 04.15pm/28May2026 
 

 Meteorological conditions and warnings for what started OFF as a perfectly normal day
 I checked IMD forecasts, warnings and satellite imagery as I normally do each morning and found it was perfectly normal, in fact there was a slight improvement from a day earlier. There was a YELLOW warning for thunderstorm in place but that is more or less the norm through out this part of the year, for this region:


Extracts from IMD Midday Weather Bulletin for 28May2026 issued by RMC, Kolkata
 
Infra -Red (IR) Satellite Imagery of 28May2026 afternoon period

Satellite image of 12.15pm which shows no major convective buildup around Kalimpong, even though there were clouds west of us, in Nepal. 
It was around this time that we had the first burst of rainfall - which I reported on 'Hazard Alerts' our WhatsApp group. A member of the group, quipped that 'there was no rain even in Kalimpong town' which is about a km away from my home - so all in all it was perhaps just a very localized shower. Excerpt of my post is below:
The rainfall returned at around 3.45pm,and this time it was serious, with intense thunder, heavy rainfall and hail at places. Excerpt of my post is below:
Satellite image of 4.15pm (below) shows an increase in clouding especially in Nepal but still does not have the 'WHITE' clouds (in IR imagery) associated with intense cumulonimbus buildups and strangely, only Kalimpong had intense thundershowers whereas there was little rain over the other neighboring hill towns. The fact that it was very localized is borne out by the fact that there was no formal RED warning from IMD or the SACHET app.
The second burst of rain turned out to be certainly the most intense rainfall I have ever experienced - luckily, like most thunderstorms, it moved towards a NE direction after sometime and rainfall decreased. 
Placed above are the rainfall and wind charts which I have downloaded from the SaveTheHills Davis Vantage Pro2 AWS which is installed at my home.
The salient findings about the thunderstorm from the above chart are:
a. We had 82.8mm of rainfall in approx one and half hours.
b. Max (instantaneous) intensity of rainfall exceeded 500mm/hr
 
24hr Rainfall (in mm) data of 28May2026 (IMD):
On 28May2026,there was no major weather system which gave Kalimpong this rainfall, rather it was an isolated cell which gave us this very localized rainfall and therein lies the danger - such weather is very difficult to forecast and difficult to detect in satellite imagery.

Kalimpong 79.2; Siliguri 40.5; Darjeeling 1.2; Pedong 2; Gangtok 2.1; Mangan 0
  
Damage/Casualties
As per the information available to me, except for damage to electric poles at places and a number of trees which were uprooted, there has not been any major damage to lives or property due to yesterday's extreme rainfall event.
This maybe due to the fact that in May2026, Kalimpong has had only 125.2mm of rain prior to yesterday's deluge and that we had only 9mm of rain in the last week.
Lucky us.

Verified video

Location: Next to Kodamull building, RCM Road Kalimpong

Need of the hour: Cleaning, maintenance, and upgradation of the drainage system.

If Kalimpong — or any mountain town — is to withstand such torrential volumes of storm water, we must urgently address the condition of our drainage infrastructure. Existing drains need regular cleaning and maintenance, while the entire system requires systematic upgradation to cope with increasingly intense rainfall events.

Photo video credits: Naresh Changia, Kalimpong

Praful Rao
SaveTheHills
savethehills@gmail.com
9475033744
 



Monday, May 25, 2026

Changes in parts a Himalayan town (Kalimpong) in 17 years


The lower photograph (May 2026) appears considerably greener than the one taken in May 2009. This is most likely because the pre-monsoon season of 2009 may have been significantly drier than that of 2026, resulting in lesser undergrowth, vegetation and seasonal greenery across the slopes.

The 2009 image also shows more open terraced cultivation and a clearer patchwork of agricultural land use, whereas these features appear less distinct in the 2026 photograph.

This change may partly be seasonal. Maize is normally planted during May and a good crop cover in 2026 may have obscured some of the terraces visible in the earlier image. However, a more important long-term factor is likely, the gradual abandonment of farmland caused by migration of younger populations away from rural areas to places abroad or to Indian metros. Many former agricultural slopes may now be unmanaged undergrowth and vegetation, making terraced areas less visible than before.

Across Areas A, B, C and D, several important changes are evident:

  • There has been a substantial increase in built structures and settlement density between 2009 and 2026.
  • This expansion would necessarily require an increase in slope cutting and road construction.
  • Much of this growth appears largely unplanned, increasing pressure on already fragile Himalayan slopes.
  • Inadequate or poorly maintained drainage systems in such densely populated hillside areas significantly increase the risk of landslides and slope failures, especially during periods of intense rainfall.
  • The spread of unmanaged vegetation may also create an increased fire hazard during dry summer months when vegetation dries out.

The one encouraging sign in the 2026 image is the apparent recovery around the Pashyor landslide area (E). Increased vegetation cover suggests partial recovery and some degree of surface stabilization. However, in the Himalayas, vegetation recovery does not always mean that a landslide has become fully stable, as deep-seated geological weakness and drainage-related instability may still persist beneath the surface.

Overall, the photographs document the transformation of the western face of  Kalimpong from a more semi-rural Himalayan settlement into a more populated and urbanized area over the past seventeen years. They also highlight the growing challenge of balancing development with ecological and geological stability in the fragile Himalayan environment.

Praful Rao
SaveTheHills
savethehills@gmail.com
9475033744

Wednesday, May 20, 2026

Using the Automatic Weather Station data to understand weather and rainfall (in this case, of Kalimpong)

The rainfall chart for the period May2025 to May2026 for Kalimpong is above and a brief analysis of the same here👇:
a. We had a fairly wet monsoon season (from approx May to Oct2025) characterized by 9 spikes when rainfall exceeded 90mm in a 24hr period. The season did start with some hiccups though:
Typical cloud image over North Bengal and Sikkim before the heavy rain of 19Jun2025
Warning on 13Jul2025 for the heavy rain (112.8mm) on 14Jul2025.

July is typically the wettest month of the monsoon season. In July 2025, there were four days during which rainfall exceeded 90 mm in a 24-hour period. Thereafter, rainfall gradually declined, apart from a brief spike on 12 August 2025. Total rainfall amounted to 467 mm in August and 253.2 mm in September 2025.

October 2025 was relatively dry, except for two days of intense rainfall. On 4–5 October, widespread heavy rain affected the entire region and triggered devastating landslides and flash floods, resulting in significant loss of life in Mirik.

These instances of spikes in rainfall are normally associated with convective clouds and normally consist of short, violent bursts of rainfall which cause high runoff and low infiltration of water (as such no recharge of aquifers) and only result in soil erosion, landslides and damage to roads.

 
After the 2025 monsoons, we went thru an extended 5 month period of drought-like conditions from November2025 to March2026.

Praful Rao
SaveTheHills
savethehills@gmail.com
9475033744 

Wednesday, May 13, 2026

Rainfall data of March/April 2026 of Sub-Himalayan W Bengal (SHWB) and Sikkim.



Despite the numerous Western Disturbances (WD) hitting the Western Himalayas during the winter of 2026, winter rains for us in the eastern end of the Himalayas were conspicuous by their absence. This was because WDs, which are responsible for our winter precipitation were tracking along higher latitudes or veering off towards the Tibetan plateau as they moved east (see satellite image above) as such never reached the Darjeeling-Sikkim Himalaya.
Forest fires in South Sikkim on 17Feb2026 due to extreme dry weather

In Kalimpong, we received our first storm and rains around mid - March 2026 but the Darjeeling-Kalimpong districts remained largely deficient in rain in Mar2026. 
Sikkim, however received far more rain in March and it is tabulated below:

Rainfall data day-wise for APRIL 2026 of some places in the Darjeeling and Sikkim Himalayas is shown below:
 
Location of rain gauge stations and rough zones of rainfall are shown:

Zone 1:  Sikkim, especially North Sikkim, received the heaviest rainfall
Among all areas in the SHWB–Sikkim, the highest precipitation occurred in North Sikkim (Mangan, Lachen, Lachung, Chungthang belt).
Zone 2.
Plains of Dooars and Alipurduar were also very wet. The foothill districts of Alipurduar, Jalpaiguri, and the Dooars experienced substantial rainfall due to strong thunderstorm activity and moisture convergence.
Zone 3.
  Darjeeling and Kalimpong hills were wet but comparatively less so Although rainfall was above normal, totals in Darjeeling and Kalimpong were generally lower than in North Sikkim and parts of the plains.
And in this region, Kurseong certainly always has the heaviest rainfall. The foothills of the Dooars ie Gorubathan and that belt also have intense thunderstorms and heavy rain.

Graphical Analysis of Rainfall and Windspeed of March and April 2026 of Kalimpong


Praful Rao
SaveTheHills
savethehills@gmail.com
9475033744