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

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.

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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