When storms change their mind - Bay of Bengal 26-29July2026

A low pressure area (see above) formed in the Bay of Bengal around the 25/26July2026 which quickly intensified into a depression and thereafter into a deep depression, more or less in the same area. 
The forecast track of the depression was initially in a NWly path:

 

The subsequent path followed by the storm and forecast by the IMD are shown (all images from  https://mausam.imd.gov.in/responsive/cycloneinformation.php):

The latest position of the storm is shown below: it is located South West of where it formed. 

Updated track of the storm as it traversed the breadth of the country (01Aug2026)

Praful Rao
SaveTheHIlls
savethehills@gmail.com
9475033744

Extreme rainfall event in the Darjeeling-Sikkim Himalayas: 04/05Oct20205 (Part I - 'The Rainfall')

 Thus far, in the SW monsoons of 2025 our region saw a deficiency of rainfall:

Sept2025 was especially dry in Kalimpong and with the monsoons expected to exit our region on 10Oct2025, one did not expect a major rainfall event.
What has been happening, however is that the Bay of Bengal has been inordinately active with bumper to bumper low pressure areas forming and many of them, after moving over land in a north westerly direction reaching as far as Rajasthan leading to excess rain in a normally arid area.

Origin of the extreme rainfall event.
Around the 29Sep2025, I posted a notice in our What's App group 'Hazard Alerts  or HA' stating a LOW was expected (by IMD) in the Bay on 01Oct2025:

The LOW pressure formed as forecast and quickly intensified into a depression by 02Oct2025

The above image was posted in our Whats App group (HA) on 02Oct2025,showing location of the depression, the forecast track and warnings issued by IMD.
An update to the forecast track of the 'deep depression' now showed the storm moving in a 'nearly northward direction' instead of the normally NW direction.

As forecast, the storm (now a well marked LOW) on 03Oct2025, reached parts of east UP (see below) and was almost stationery there until 04Oct2025.

The storm finally started moving as predicted in a NNE direction, heading directly towards Bihar, SHWB (Sub Himalayan W Bengal) and Sikkim at approx 3pm on 04Oct2025 (yesterday), below:

In the top image, do note the density of lightning strikes which were taking place.

Rainfall data
03Oct2025: Despite having a RED warning for heavy rain, our entire region received very little rain. I distinctly recollect that in Kalimpong (my home), it was a densely overcast day which turned stormy around midday but except for some drizzle, there was no precipitation.

 04Oct2025: I was monitoring the Davis Automatic Weather stations in our area and we had light rain from  around midday. At Kalimpong, it started thundering in the late evening and by 7.30pm, the thunder had intensified. Thereafter, the rainfall, lightning and thunder continued thru the night with little or no break

windy.com image of 11pm/04Oct, just when lightning and rain was increasing over our area. The storm had moved from its earlier location and was approaching us from the SW.

Rainfall Intensity at Kalimpong

The above graph showing the rainfall intensity at Kalimpong on 04Oct2025, also shows the duration of the rainfall. Peak intensity of rainfall almost hit 150mm/hr and almost the entire 158mm of rain came down between 8pm and 4am ie 8hrs.

Lightning strikes at 3.30am/05Oct2025. The storm exited our area and continued NE wards about an hour later having killed 23 people.

Rainfall readout from our Davis AWS at Kurseong at 4.13am on 05Oct2025 (today). Kurseong is known to have heavy rainfall and has some very large landslides there. The rainfall from the extreme event was 393mm.

Praful Rao
SaveTheHills
savethehills@gmail.com
9475033744

We will cover the casualties as well as the damage done by one day's rainfall on 04/05Oct2025 in Part II to this post.

ALL ABOUT CYCLONES: How cyclone track forecasts can change dramatically and how climate change maybe impacting them.

 We have been tracking the storm in the Bay of Bengal for several days now (as we normally do) and have been posting updates in our WhatsApp Group 'Hazard Alerts'.
On 26Nov2024, the forecast from IMD clearly said that the storm would intensify into a CYCLONE

This was changed and on 28Nov and the storm was expected to remain a 'DEEP DEPRESSION' and make landfall on 30Nov2024 as a 'WELL MARKED LOW' (see below)

The forecast was revised the next day and the track showed the storm intensifying into CYCLONE 'FENGAL'on 29Nov2024.
The latest forecast track from IMD of 'FENGAL' together with WARNING no '3' from JTWC is reproduced below.

The tracks from IMD and JTWC seem to coincide.
I am also posting an article from today's Statesman on how climate change maybe impacting cyclones in the Bay of Bengal

Praful Rao
SaveTheHills
savethehills@gmail.com
9475033744

Extraordinary rains of September end 2024 (in the Darjeeling - Sikkim Himalaya).

Until the 23rd, the month of September 2024 for us in the Darjeeling-Sikkim Himalaya turned out to be very dry and inordinately hot, prompting a member of the SaveTheHill's What'sApp group 'Hazard Alerts' to write:

'What does it mean, no rain in Kalimpong, Sikkim or Darjeeling?? Paddy fields are drying, springs and streams have dried already, this year "MUL PHUTENA", meaning ground aquifers were not recharged completely. This situation warns of the chaotic food insurgency especially to those who wait for food from farmers. Poor farmers look at the sky, it looks blue, no cloud, and he screams for his hardships and crop failure. I'm a farmer, what option do I have now??'

Another member post this cartoon about the prevailing hot weather:

Then on 24Sep2024, another LOW pressure area, in a series of bumper to bumper lows which had formed in the Bay after 17July2024, developed as shown below:

IMD issued a number of press releases about the weather systems causing the heavy rain and likely weather which would ensue:

Based on IMD and other inputs, STH posted satellite imagery and weather updates continuously during the period in our WhatsApp groups 'Hazard Alerts, Hazard Alerts 2, Hazard Alerts 3' - we also used other social media handles to publicize the heavy rainfall warnings.

Rainfall data

On 29Sep2024, IMD gave us a GREEN (ie no warning after 3 days of RED warning and 1 day of orange warning in the above period) and we had a dry day after 5 days of non-stop rain.

The average monthly rainfall for September in Sub-Himalayan W Bengal and Sikkim is 388.1mm - the 5 day rainfall of Sept2024 end, as seen above came close to or in the case of many towns, exceeded the monthly average and thus we swung from a total deficiency of rain in the first three weeks of September to a gross excess of rain, all of the large volume of water coming at the end of the monsoons when the mountains are almost saturated with water. As such the impact of this unusual heavy rains was huge in the region.

IMPACT

Firstly and most importantly, there were no fatalities even though we did have many landslides and near misses.
Road Communications: NH10
The already poor state of road communications especially in the Teesta valley suffered further set backs.

Landslide on NH10 near Teesta bridge on 27Sep2024 (27 03 40.2 N 88 25 35.3 E)

Large landslide on NH10 near Melli (27.08388889N 88.45098611E)

Other places in the Teesta Valley

Flooded Darjeeling - Kalimpong road near Teesta bridge, 28Sep2024. The debris and sand deposits by the GLOF of Oct2023 had raised the level of the Teesta river by as much as 4-5m so heavy rain
always results in the river flooding this road.

Teesta Low Dam Project III at 27Mile and the flooded Bangay bazar bridge
(26°59´38.20´´N 88°26´32.83´´E)

Flood affected areas of Teesta bazar. As mentioned earlier, the GLOF of Oct2023 has pushed the riverbed levels up by 4-5m and as such the river runs perilously close to many densely populated areas - Melli, SIngtam and Rangpo to name a few. Heavy rain in the valley invariably results in flooding of these areas.

Melli town and stadium ( 27°05´23.03´´N 88°27´28.01´´). The stadium which was entirely covered by debris and sand by the GLOF in Oct2023 had been painstakingly cleaned by the town but it has been rendered unusable by the repeated flooding of the river.

The GTA Covid Hospital (27°04´48.63´´N 88°25´50.37´´E) lying derelict on the banks of the Rangeet river since the GLOF of Oct2023. Parts of the one lane road leading up to the hospital from Teesta Bazar has been under the river for a year now and the recent rains have inundated even more areas of the road.

Other parts of the Kalimpong and Darjeeling districts

Major landslide in the vicinity of Kalimpong town at the by-pass road, 7th mile (27 04 13.9 N 88 26 56.8 E). In Sep 2024, Kalimpong received less rain than Darjeeling and Kurseong and as such we never had as many landslides.This large landslide took place on 28Sep at around3.30pm.

Subsidence due to mountain stream erosion (jhora) in a densely populated area of Kalimpong municipality (27 03 47.0 N 88 27 45.8 E). The subsidence (seen here covered by plastic sheets to prevent water ingress) occurred during daytime on 28Sep2024 when the stream was gorged with runoff from upstream paved surfaces. My concern here is that this whole area is located above a landslide prone zone on which we have done a story in 2010.

Landslide in the Darjeeling Municipal area at Hooker Road, on 26Sep2024

Landslide at Lower Bhaktey bustee in Darjeeling

Sikkim received much less rainfall in late Sep2024 resulting in much less devastation and landslides.

I am sure there were many more unreported landslides and instances of flooding caused by the unusual heavy rains and we will keep updating this blog on the reports, when received. We will also be surveying the affected areas in due course of time.

My thanks to all HA members whose images and reports I have used liberally here and elsewhere - all with the intention of recording the event for posterity.

Documentation of parts of the above report was supported by Royal Enfield, as part of their Social Mission Initiative


Praful Rao
SaveTheHills
savethehills@gmail.com
9475033744

STH stormwatch : LOW pressure in the Bay of Bengal.

SaveTheHills Stormwatch is a series where we track and report on significant weather developments in our region not only to forewarn our communities (which we largely do today through our WhatsApp Group 'Hazard Alerts 1& 2') but keep a record of the event.
As on 20Oct2023, a low pressure formed in the central Bay of Bengal which is likely to intensify into a depression by 22Oct and move towards the Bangladesh and West Bengal coasts by 24Oct2023.
The Darjeeling-Sikkim region has just seen catastrophic flooding and destruction in the 04Oct2023 GLOF from South Lhonak glacier and being located barely 600kms from the Bay of Bengal any major storm in the north Bay will probably impact our region and which would hamper all reconstruction activities and make lives of those who have lost everything even more difficult.

 

Update on 22Oct2023

IMD has posted to its first forecast track (above) on the probable path of the storm

Update 24Oct2023: Cyclone 'HAMOON' is born
JTWC's forecast track

IMD latest forecast track

Kolkata reported moderate rainfall for sometime on 23Oct2023, but largely the storm seems to be keeping clear of the city.

Praful Rao
Kalimpong district
Darjeeling-Sikkim Himalaya
savethehills@gmail.com
9475033744