Heavy rains in the Darjeeling-Kalimpong region on 08/09Aug2023.

The meteorological conditions which led to the heavy rains are given below:

The satellite images of 08/09August2023 which were posted in our What's App group are shown:

In Kalimpong, the rains started at around 7pm and continued through the night even though the intensity was less around midnight. The rainfall intensity graph from a Davis Vantage Pro2 AWS at my home in Tirpai, Kalimpong is given below:

Unlike the localized rains of 01Aug2023, rainfall on 09Aug occurred over larger area  and included the towns of Darjeeling and Kurseong. The rainfall distribution map is given below:

The heavy rains 01Aug2023 (165.4mm) and that of 08Aug2023 (131.2mm) together add up to 296.6mm against a monthly rainfall in Aug of 495.2mm - as such we received 59.89% of our monthly rain in just two days.
Landslides
Landslides were reported in
Kalimpong - Echay bustee
Darjeeling - Rimbick
Darjeeling- Pul Bazar

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

Highly localized, extreme rainfall in Kalimpong :01Aug2023

With a deep depression in the north Bay, 01Aug2023 started off in North Bengal and Kalimpong as a warm, dry day and remained so most of the day. There was little indication of the severe weather which was looming in the evening and IMD had issued only a YELLOW warning for our region.
The first patches of cumulonimbus clouds appeared in the satellite image at 5.45pm.

Thundershowers started around 6.30pm and continued nonstop till 11.30pm. Rainfall intensities remained high as can be seen from the graph.

What was very surprising was that the rainfall was very localized with the precipitation only occurring in Kalimpong. Other towns in the vicinity had the normal expected rain - only Jhalong and Rongo in the far east of Kalimpong district showed the extreme rain as was experienced in Kalimpong.

Even though landslides did occur, their prevalence was not high - perhaps because of the meagre rainfall received in north Bengal in the latter half of Jul2023 and the consequent decrease in the moisture content of the soil.

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

Extreme thunderstorm at Kalimpong (20Sep2019)

Photo credits : Ms Shreya Gurung

* Having worked on the landslide problem of this region, I am very worried when we have intense rainfall towards the end of the monsoons. Some of our major landslide events (Oct 1968, Sep2007) have taken place at this time when the soil is saturated in the months of monsoon rain and a heavy downpour occurs triggering slope failure.
Last evening, we were lucky - the rainfall was extreme and intense reaching 215mm/hr and staying over a 100mm/hr for a good 20mins. Maybe what saved us was:
a. The past 10days have seen deficient rainfall with the last 2 days being dry.
b. The storm quickly moved away from us and within an hour we were dry again.
* And this seems to be the new normal where we alternate between rainfall deficiencies and surplus, where we either have no water and our fields and springs are dry or when we have so much water that it causes landslides and death.
* Having said this, I would also like to bring to light the recent landslides in Tsong, Yuksom area of Sikkim where there was no warning of heavy rain in the area as in the case of Kalimpong yesterday. These small local weather events which can result in heavy downpours but do not show up on satellite imagery and therefore give no warning are increasingly the ones we must guard against.


Total rainfall in the thunderstorm on 20Sep2019 42.7mm



Praful Rao
Kalimpong district
Darjeeling-Sikkim Himalaya

Winter rains and precipitation in the Darjeeling-Sikkim Himalaya (16Feb2019)

Placed above are IR images of clouding over the Darjeeling-Sikkim Himalaya of time 0530hrs and 1230hrs. The clouding is due to one of a series of WDs which has been affecting the western Himalaya first, then sweeping east towards us.
In Kalimpong there was continuous thunder and lightning from around 1330hrs till 1830hrs though the rainfall was only light. Darjeeling on the other hand was swathed in a blanket of hail. Read more here.

In this regard, I am placing the explanation to this weather event, below:

Praful Rao,
Kalimpong district,
Darjeeling Sikkim Himalaya

Weather Event : Hail storm in Darjeeling (31Mar2016)

In Kalimpong, where STH is based, the cumulonimbus clouds (top slide) brought in grouchy weather with a lot of lightning and thunder but surprisingly little rain.
IMetD has a weather warning in place for TS (Thunder Showers) and Hail for this region.
Though much of the chatter on social media was on how beautiful Darjeeling looked and ice-skating in Chowrasta, Darjeeling - what was missed was the damage to tin-roofed homes, the traffic jam in Darjeeling town when the schools gave over at around 3pm and perhaps the damage in the rural areas, which is not known at all.

Precipitation in Darjeeling : As per reports, 6" of hail along with 45mm of rain
                                       (between 1.30pm- approx 3.00pm)
Rain in Kalimpong : 3.8mm (between 1pm-3pm)
Rain in Kurseong : 16.6mm

Photo credits :
Compuset, Darjeeling
The Darjeeling Chronicle

At last, welcome rains in the Darjeeling-Sikkim Himalaya : 30Mar2015

If March2015 was the wettest in the last 100yrs for much of North and Central India (see here), then it must have been one of the driest in the Darjeeling-Sikkim region (see Slide 1)
From Oct2014, when the SW monsoons receded from this area, till 30Mar2015 we had no significant rains leading to bone dry conditions which caused raging forest fires (Slide 2), a severe potable water crisis in most urban dwellings in the region and dust/smoke haze which lowered visibility and resulted in months of atmospheric obscurity.
On 30Mar2015, the same storm system (Slide 3) which caused flooding and 16 deaths in Kashmir, barreled its way towards the Darjeeling-Sikkim Himalaya, brought in sharp thundershowers at 4.40pm.
Rainfall data for 4 places in this region is placed below :-
Kalimpong - 22mm
Darjeeling town - 17mm
Aap Botey(Mineral Springs- Darjeeling) - 20.2mm
Mangan (N Sikkim) - 37mm

Praful Rao,
Kalimpong,
Darjeeling district.

Welcome rains in Kalimpong - 27Apr2014

The entire north-east of India has been tinder dry after the SW monsoons of 2013 (We currently have 48% deficient rain in our region with the other north east states going upto 67% deficient - top slide)
Most areas are reeling under a severe water shortage in the Darjeeling-Sikkim Himalayas and numerous forest fires have been reported all over the region.
In this scenario, the sharp and heavy thundershowers brought about by a dense blob of CB clouds (IR satellite image of 27Apr2013, time 5.30pm), came as a welcome relief.What it also revealed was how unprepared we are for the onset of the monsoons 2014 with clogged drains and torrents of storm water turning roads into rivers.

Rainfall
Kalimpong - 34mm
Darjeeling - 13mm
Gangtok - 10mm

Praful Rao,
Kalimpong,
Dist Darjeeling

Landslide report (18April2013) ie (02/2013) : Small landslide in Kalimpong

Preliminary inquiries reveal the slide occurred in a village located directly below Kalimpong  due to a mountain stream (Botey jhora, in this case) being overloaded by surface runoff from built up areas of the town during the heavy thundershowers.
This is a well known cause for landslides around urban areas in this region and has also caused much of the landslide fatalities in the area.
Much has been achieved by the scientific community in the study of science of landslides but I daresay little has been done in studying the rate and scale of devastation of land and loss of livelihoods by landslides.

Photo Credit : Mukesh Sharma, Janpath Samachar

Praful Rao,

Kalimpong