Heavy rainfall event: Targeted rainfall over Kalimpong town and its immediate surroundings on 21Jul2026

The type of rainfall Kalimpong witnessed last evening and which continued for the whole of this morning (21Jul2026) was what we expect during the month of July in this region...steady and continuous rain which can turn heavy at times. 
There was no thunder or lightning, just the steady drumbeat of heavy rain for hours on end. The graph above shows just that with the rainfall intensity remaining above 50mm/hr for much of the time.
That was not surprising, what was very surprising to me was the fact that the rainfall was very targeted and confined, affecting only Kalimpong town and a small area in its vicinity. The map below reveals this and rainfall figures above 100mm are in RED.

Darjeeling received 74.2mm of rain and Kurseong which normally receives the heaviest rain among the hill towns received only 51.4mm. The rainfall figures in black are all below 50mm.
 
The Infra-Red (IR) cloud imagery (below) of this region of 06.15am today shows nothing which could have caused such heavy rain over Kalimpong while causing only 9.6mm over Siliguri and 8.3mm over Gangtok.

The rainfall caused a small urban landslide near my home in Tirpai Kalimpong this morning. The drone image of the landslide is placed below (27° 4' 37.308" N 88° 29' 17.43" E - drone lat/long). Do notice the densely packed homes which seems to be the direction in which every mountain town in the Himalayas is heading.

Praful Rao
SaveTheHills
savethehills@gmail.com
9475033744

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 

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 

SaveTheHills photo exhibit on 'The Teesta Valley GLOF disaster - the unheard voices' renewed till April2028 (by Social Documentary Network).

Exactly a year ago, I published a report on the Social Documentary Network (SDN) titled “Teesta Valley GLOF Disaster – The Unheard Voices.”

For those unfamiliar, SDN is a ‘global platform for documentary photographers and visual storytellers, with a strong focus on social, environmental, and human-rights issues, featuring the work of around 3,000 photographers worldwide’ (ChatGPT).

A few days ago, I was notified by SDN that the GLOF exhibit was due for renewal, which involved a fee in US dollars. However, there was also an option to apply for a fee waiver. I’m happy to share that considering our work, SDN has graciously waived the renewal fee until Apr2028.

This means our Teesta Valley GLOF exhibit will continue to remain accessible on a respected international photojournalism platform. I have also updated and refined the exhibit, and it is now available to view here.

I would urge you to take a look and share it further. The disaster remains largely unknown beyond the region, and greater awareness is essential so that the scale of the tragedy—and its continuing impact—is not forgotten.

Praful Rao,
savethehills@gmail.com
9475033744

About politics and managing disasters - Davis Automatic Weather Station (AWS) distribution in Sikkim and Sub-Himalayan West Bengal (Darjeeling and Kalimpong districts)

SaveTheHills has long recognised the critical need for real-time weather data in the Himalayas, where conditions can shift rapidly and with little warning. Since 2016, we have operated Davis Vantage Pro2 AWS units at two locations and have consistently highlighted the need for a denser network of such stations across the mountain region.
Kalimpong and Darjeeling are two adjoining hill districts of West Bengal, while Sikkim—though a separate state—forms a contiguous stretch of the same Himalayan terrain. In fact, according to Google Earth, my home in Tirpai, Kalimpong (West Bengal), is just 2.185 km from Melli in South Sikkim.

So I was rather surprised when I read this article in papers today about the inspection of 67 AWS in Sikkim state:

All 67 Davis AWS units in Sikkim were supplied by the Government—specifically the Department of Science and Technology (DST)—and the India Meteorological Department (IMD) is now working with DST to upgrade and overhaul these stations.

In contrast, the hill areas of Darjeeling and Kalimpong districts have only five Davis AWS, all installed through the independent efforts of NGOs and private individuals. These units are operated and maintained entirely by us, without any government support. 
The locations of AWS:-
1. Kalimpong (operated by SaveTheHills)
2. Kurseong (operated by SaveTheHills)
3. Pedong (operated by Bal Suraksha Abhiyan)
4. Todey  (operated by Bal Suraksha Abhiyan)
5. St Paul's School, Darjeeling (operated by the school)

One Davis Vantage Pro 2 AWS was installed in Gorubathan (W Bengal) by the Kalimpong district administration some years ago but has steadfastly remained defunct thereafter.

Comparative Size and Population of Sikkim and Darjeeling/Kalimpong.

Size of Hill areas of Darjeeling and Kalimpong districts: 2,478.31 km²
Population of Darjeeling and Kalimpong districts: 875,713.
Size of Sikkim: 7,096 km²
Population of Sikkim: 610,577
                                                                                - source ChatGPT

SaveTheHills had also reached out to the district administration for support in expanding AWS coverage in Darjeeling and Kalimpong. A formal letter to the Gorkha Territorial Administration (GTA) was drafted on 30 December 2021 and handed over at the time to a senior party official. The letter is reproduced below:

The letter has not seen the light of day since then and we in Darjeeling/Kalimpong continue to work with only 5 Davis AWS.

If political differences lead to such uneven treatment of regions that share the same geography, face identical hazards, and are equally vulnerable, then our ability to manage disasters becomes severely compromised. This is especially troubling in the Himalayas, where the landscape is far more fragile and exposed to multiple, overlapping hazards.

Praful Rao,
savethehills@gmail.com
9475033744